2. REVIEW OF LITERATURE
The study of plastic degradation specified that greatest of the respondent,
nevertheless of their experience, are in facility of banning of large scale manufacture,
circulation and use of these polymers, and are conscious of the opposing belongings of
plastic container wastes on environmental hazards, and finally animal and human
fitness. Nevertheless, plastic bags are quiet extensively used by the public additional
than any other mostly due to their cheaper cost and large scale production (Adane, et
al., 2011).
The Pseudomonas spp. from three diverse terrestrial locations (P1: household
garbage dump; P2: soil from textile effluents drainage site; and P3: sewage sludge
dump) were isolated and characterized basing on their morphological and biochemical
characteristics. After 8 weeks of incubation was found to degrade both natural and
synthetic polyethylene very efficiently with 46.2% for T1 (Pseudomonas + natural
polyethylene) and 29.1% for T2 (Pseudomonas + synthetic polyethylene).
In contrast, P1 (i.e. Pseudomonas from household garbage dump) gave the
lowest biodegradability of 31.4% for T1 and 16.3% for T2. However, P2 (i.e.
Pseudomonas isolated from textile effluents drainage soil) gave an intermediate
biodegradability of 39.7% and 19.6% for T1 and T2, respectively (Nanda, et al., 2010).
The paper review found that Aspergillius fumigatus and Penicillium sp. were
natural to the places of plasyic removal and capacities indicates definite decomposibility
in regular situations and so similarly biodegradation in laboratory situations on artificial
media. Conferring to this review bacteria cause highest degradation of polythene and
plastics. (Singh, et al., 2012).
In this review work was carried out on biodegradability of polymers by using
microorganisms and the polymers are natural and synthetic types. Disposal methods
were used for the biodegradation of polymers. Numbers of test were used for the
determination of biodegradation of microorganism. Many of the microbes are active at
aerobically or some anaerobically. In experimental work weight loss of polymer,
physical, chemical properties were measured. (Shaha, et al., 2008).
In this review the experimental work done for eight months. Biodegradation of
potato starch founded low density polyethylene (LDPE) was examined in soil rich in
microorganisms for 8 months.
The control and treated polymer samples weight were measured for the rate of
degradation and therefore their difference was indicated the biodegradation of polymer.
In this study thirteen bacterial strains were isolated and their genus is the
Shewanella, Moritella, Psychrobacter and Pseudomonas. This is the first report that
PCL-degrading bacteria were isolated from the deep-sea environments at depth over
5,000 M.
Results indicated that the hydrostatic pressure and temperature effect on the
growth of the isolates, the isolates belonging into the genera Shewanella and Moritella
were shown to be psychrophilic high-pressure adapted bacteria.
It is demonstrated in this study that some biodegradable plastic materials might
not be able to be degraded by deep sea microorganisms, thus to identify new
biodegradable materials for ocean environment (Sekiguchi, et al., 2010).
This paper PP has a methyl group in place of a hydrogen current in polyethylene,
on each further carbon, that provides increase to the existence of three stereo-isomeric
arrangements namely, atactic, isotactic, and syndiotactic (Baker et al., 2002).
These paper results indicate that the industrially applicable PE was first
synthesized in the year 1933 by Eric Fawcett and Reginald Gibson at ICI chemicals
(Trossarelli et al., 2003).
Poleethylene is entirely linear and accessible with flexible variety of thicknesses
from 0.91-0.97 g/cm3. Short density polyethelene has intense at accidental spaces
which indications to little packing of the polymer chains, however the high density
polyethylene is additional linear with negligible splitting that leads to high packing
density (Baker et al., 2002).
Results show that Biodegradation depends upon polymer characteristics,
organism type and nature of pretreatment (Shah et al., 2008). The pretreatment of
polyethylene is very significant for its biodegradation. Physical rupturing of the
polyethylene and chemical washing by ethanol might have added value to its
degradability.
To support this, Volke-Sepulveda et al. (2002), proved that adding ethyl alcohol
to fungus culture that contains polyethylene boosted the rate of polymer degradation.
Despite the fact that the isolated microorganisms were innate to the place of
polyethylene dumping and capacity show sure degradation in normal situations, even
they also indicated biodegradation in laboratory situations on artificial media. (Nanda et
al., 2010).
Poly-β-Hydroxy Butyric acid (PHB), a biodegradable polymer was produced by
fermentation technology of two-stage cultivation process. The organisms used were
Alcaligenes sp. and Pseudomonas sp.
The produced PHB was exacted using sodium hypochlorite digestion process
followed by solvent extraction technique. PHB was identified using by Thin Layer
Chromatography and it was quantified spectrophotomertrically at 235 nm. The
optimized condition observed for the PHB production was 48 hr of time in the Nitrogen
Free Molasses medium.
The production of PHB by Alcaligenes sp. (890 µg/ml) was found to be high
compared with Pseudomonas sp. (875 µg/ml).
The produced PHB was characterized using IR spectroscopy. The extracted PHB
was tested for its degradation by overlay method. The PHB was finally subjected to film
preparation using Poly ethylene glycol (PEG) (Kirithika, et al., 2011).
The rate of breakdown rises with rise in temperature and it is increase by
molecular oxygen and even more by radicals. Diffrenet products were known in all
reaction products, which formed in breakdown and recombination reactions. therefore,
besides chemical structure and effectiveness, the heat stability of phosphorous
stabilizers has to be taken also under consideration in their application, as it plays an
main part in the process of stabilization of polyolefin (Ildiko., 2010).
In this review species of Aspergillus glaucus, A. niger, Pseudomonas species
and Moraxella species were used for the biodegradation experiment. The experimental
set up were occurring for one month. The biodegradation of plastic were done up to
28.8 % within a month’s (Seneviratne, et al., 2006)
This work dedicated on the opportunity of rise process of biodegradation, the
short thickness plastic. Proportional research among the possessions of control sample
of LDPE pieces and the one which were showing to UV radiation and nitric acid plus
microbial culture action.
It was specified that in case of UV and nitric acid experiments LDPE points
appeared at 1710 cm-1 and 831, which were then decrease to 1708 cm-1 and 831 after
microbial action, presentating breakdown of polymer chain.
It is visibly observed present study that a synergistic effect of U.V. nitric acid and
microbial action encouraged oxidation reaction that improve and increase the
biodegradation rate of LDPE pieces. (Shah, 2007).
Bacteriological biofilm formed on abiotic surfaces is an important area of
research because of the wide range of all possible effects and the disinfectant
resistance of the cells. The colonization of solid surfaces by microorganisms is a very
complex process that rely mostly on extracellular molecule production. The biosynthesis
of EPS reflected the attachment and combination process so also providing an optimal
environment for the give and take of genetic material in between the cells.
The microorganisms are able to degrade one and two ringed aromatic
hydrocarbons down to 1 ug/l or lower with a fairly high reaction rate, given sufficient
oxygen and nutrients.
A high degradation potential by bacteria in the bulk ground water in gasoline- and
fuel oil contaminated areas has been observed. These free flowing bacteria are
transported by the groundwater, and consequently the bacteria may play an important
role for degradation further downstream the spill area (Jensen, et al.).
In this review different types of plastic were used for the biodegradation and
Pseudomonas species were used for the experiment. In the results it was observed that
the adsorption of organisms to the surface of polymer. And then the cleavage process
occurs.
In the experiment additives like starch were used for the experiment. Organic
chemical substance degradation of nylon continues complete drastic erosion (Premraj
et al., 2005).
In this research paper the isolation and characterization of polyethylene
degrading bacteria from polyethylene garbage was done. Bacterial strains were
successfully isolated from polythene garbage dumps. The identified bacterial species
were E.Coli, Staphylococcus, Pseudomonas, Klebsiella and Bacillus. he degradation
was observed by changes in physical and optical characterstics. The percentage of
Kathersan that Pseudomonas sp degraded the plastic upto 8.16% and 20.5% of
degradation was observed anaerobically.The maximum degradation was observed in
staphyloccussp. The maximum amounts of polyethylene degradation by weight loss
method were observed (Pande et al., 2014).
The one type of plastic is the Synthetic polymers and is called as plastics. These
are applied in a major range of packaging, household, and architectural applications
and many other related fileds. Plastics were developed as light-weight, and durable
materials and they have replaced natural resources, such as metals and stones.
However, its properties of durability have caused serious problems since waste
polythine accumulates in the surrounding. The accumulation of abandoned plastics has
caused a global environmental problem. Nature usually cannot handle plastic waste,
Addition of microorganism in the soil are necessary for biodegradation because plastic
are increased in the environment. At present, about one hundred million tons per year of
plastics are produced in the world. With the increase in production,the amount of
plastics wastes has raised enormously (Mukai, et al., 1995).
In this research the response for biodegradable plastics continues to grow and is
influenced by several factors including the continued increase of crude oil prices,
consumer demand for more environmentally friendly products, and increased
restrictions on the use of nondegradable plastic products. To avoid disrupting the
ecosystem, plastics needed to be recycled, other than creating chemical or biological
imbalances. Biodegradable plastics from renewable sources that allow cyclic process to
be done over minimum time internals usually minimum a year and fit nicely with
naturally occurring carbon cycles in the environment. Another benefit of producing
plastics from renewable resources is the reduction of fossil fuel derived CO2. The
synthesis of monomers and polymers by enzymes, microorganisms, and plants displays
a cleaner and more sustainable process. The progress of techniques, especially genetic
engineering, will allow microbes and plants to produce biodegradable polymers or their
monomers more efficiently from inexpensive bio based and renewable carbon sources.
Based on financial and surrounding deliberations, the mercantile of biodegradable
plastics will keep increasing in the market. It has been estimated that the production of
biobased plastics will rise since 360,000 tons in 2007 year to around 2.3 million tons by
the year 2013. Potentially for up to about 90% of total plastic consumer replaced by
biopolymers is technically possible (Qin Wang, et al., 2010).
In this research paper the isolated bacteria was Pseudomonas stutzeri. It was used
for the biodegradability experiment of LDP and PP. Tensile strength (TS) and
extension of treated plastic films with and without the inoculum were studied
experimentally at 15 d interval. The changes in per cent extension, tensile strength, and
elongation were analyzed. There was reduction in per cent extension, which was found
to be maximum in polypropylene, 6.4 per cent more than in low density polyethylene
and 13.3 per cent in comparison to control. Tensile strength was found to decrease
with increase in incubation period on polypropylene. Steep reduction in elongation was
recorded in both the plastic films with increased incubation time with a minimum 2.5
cm reduction observed in polypropylene. The minimum per centage change in the
tensile strength was in LDP on 15th d i.e.18 per cent and maximum was observed in PP
on 45th d, i.e. 66 per cent. Study indicates the rise in tensile strength, many a times with
reduction in delay, in the initial phases of degradation. This presence surveyed by a
reduction in ductile asset and additional decrease in extension (Sharma, et al., 2003).
Low density polyethylene (LDPE) films were placed in pond water at laboratory
condition and room temperature for more than two years. Biofilm that developed on the
material was examined for microbial type and erosion characteristics. Samples which
showed considerable deformities in surface morphology were selected for subsequent
cultivation and isolation of dominant microorganisms. Organisms well adapted to grow
on LDPE films in nutrient deficient environment were used to study their ability in vitro to
degrade LDPE asper guidelines of ASTM, ISO authorities. In liquid culture, the value of
total water soluble organic carbon(TOC) increased threefold after 14 days of incubation
but dropped below initial level within next twoweeks. 15 to 58 % coverage by
Penicilliumsp. only after 65 days and 44 to 81 surface growth ofHumicolasp. on LDPE
film showed their affinity towards polyethylene. In clear zone assay, no halo
zonesaround the colonies were observed but all bacterial isolates showed superior
growth in the presence of polyethylene (Husna, et al., 2006).
In this research paper study done on Low density polyethylene type of plastics.
The prior objective of this study is to isolate and identify the microorganisms from soil
during biodegradation testing of polyethylene/starch film. Serial dilution method is used
for the isolation of microorganism. Culture media is used for the multiplication of isolated
microorganism. The temperature 370 C is maintained for the growth of microorganism.
Identification of microorganisms was carried out by macroscopic and microscopic
examination. During identification it is found that Bacteria like Pseudomonas spp,
Streptococcus spp, Staphylococcus spp, Micrococcus spp and Moraxella spp etc, fungi
like
Aspergillus niger, Aspergillus glaucus etc, and Actinomycetes are present on the
surface of polyethylene/starch film. Surface morphology of polyethylene or starch film
has been analyzed by scanning electron microscopy (SEM) before and after
degradation. Physico - mechanical properties has also been determined before and
after degradation of film in order to understand the rate as well as the mechanism of
degradation. (Sharma, et al., 2013).
In this paper study was complete on decomposable polymers for nutrition
packing material. The highest objevtive was to present elements inducing polymer
degradation and biodegradation in different environments. It was well-known that
biodegradable polymers are an deficient alternate for classical polymers and its
decomposition strongly depends on degradation situation. It was also observed that
there are numerous methodologies in different countries to certification of biodegradable
polymer materials, this is quite complicating its application than promotes it (Guzman,
2011).
This review show that there are little plastics that resist degradation and certain
of them degrade it to sure level. Even limited of them remain as determined carbon-
based contaminant. The researches are about the degradation of several categories of
polymers in biological means and several further means.
The review dedicated that all types of the polymer study done and treated with
different types of microorganisms. Bacterial and fungal species are generally used for
degradation of polymers. Different strains of Pseudomonas species were used. The
bacteria that degrade the compound of hydrogen and carbon present in the polymers
and use by them as carbon source.
Certain of the microbes involved were Pseudomonas spp., Xanthomonas spp.,
Flavobacterium spp., Micrococci, Streptococcus, Staphylococcus, Bacillus,
Phanerochaete chyrosporium, Penicillium frequentans, Bacillus mycoides,
Pseudomonas putidaVM15A, Streptomyces spp., and Aspergillus spp. The outcomes
found are then confirmed by the elements like weight, tensile strength and reduction in
thickness in some cases, molecular weight distribution, and breakability. This has
displayed that HDPE polymers are resistance to soil conditions than LDPE.
This study is suitable for formulating the molecular intend of biodegradable
polymers and for the molecular progress and breeding of degradating organic chemical
substance and microorganisms. The biodegradation by enzymes of secretion was also
seen to be fruitful.
The pure culture biodegradation examine the capability to analyze which part of
the degradation is because of chemical degradation and what can be recognized openly
to biotic degradation by the microbes. By means of these studies degradation of
polymer can be ended effective (Gnanavel, 2012).
The present research paper study focused on selection compost samples for
various poly lactic acid plastic degrading microorganisms. Five isolates were identified
as potential degrading microorganisms. The isolate MS-4 found to be yeast and all
other four isolates were Gram positive bacilli.
Degradation changes in the PLA film were determined by measuring weight of
dry residual PLA film. In the absence of compost isolates, reduce in the weight of PLA
film was rarely observed. On the other hand, isolate MS-2 showed 45.5% of weight loss
within 15-20 days of incubation. Whereas, only 4% weight loss was reported after 40
days of incubation with Bordetella pettri PLA-3.
It clearly indicates the involvement of compost mesophiles of the present study in
the degradation of polymer. In the presence of polymer film, hike in TOC value was
seen from the initial phase and reached maximum after two weeks of degradation and
then decreased gradually. Similar results were observed in degradation of PLA film with
Geo bacillus thermo catenulatus and Amycolatopsis mediterrani.
These results recommend that the PLA film has been used as carbon source and
the growth of bacteria was induced by the assimilation of soluble degradation products
which corresponds to decrease in TOC at later stages. SEM inspections had shown the
presence of a bio film, which suggested microbial degradation. The SEM image of PLA
film exhibited opaque and rough surface with irregular holes and the PLA film was
totally mutilated due to the growth of isolates MS-1, MS-2 and MS-3. In contrast, the
scanning electron micrographs showed no significant changes of the sample
morphology in the absence of isolates.
It is obvious fact that the creation of biofilms by microbes linking and increases
their connection to surfaces and stimulate them to live under small nutrient environment
and used solid substrates.
The degradation potential of mesophilic strains was also confirmed by clear zone
assay method. Pranamuda and Tokiwa, isolated 25 Amycolatopsis strains out of which
15 left clear zones on agar plate emulsified with polylactide, displaying a big distribution
of plastic dishhonour within the genus. Nakamura et al., isolated Amycolatopsis strains
K104-1 and K104-2 which have the capability to form prominant areas on the PLA-
emulsified agar plates surface at 37oC. Based on the zone of hydrolysis on emulsified
PLA agar plates, MS-2 was selected for further identification.
The identification of isolate MS-2 was carried out with standard method and
analysis of 16Sr RNA of isolate MS-2 was identified as Bacillus amyloli quefaciens.
This was found to be a decent one bearing plastic degradation motion in
surrounding environment as it has slight phyletic match with other plastic degrading
microbes as described before.
The results demonstrate that the purified enzyme is protease that was
contributing in the bacteriological degradation of PLA.
The esterase type degradation of PLA has been reported only for PLA
depolymerase from a thermophile Bacillus smithii. From the present study, it can be
concluded that PLA was significantly degraded by Gram positive mesophilic bacteria i.e
Bacillus amyloliquefaciens with serine protease as PLA depolymerase (Prema, et al.,
2013).
The existing research that was achieved to understand the abiotic mechanism of the
degradation practice, and numerous corporeal, organic and biochemical methodologies
that can be recognized to increase their biodegradation of plastic are studied.
Genomic engineering methodologies to rise the presentation of the
bacteria or computational methods to motivate the degradation paths could be the
coming to growth the degradation level of these polymers (Arkatkar, et al., 2009).
This review studied sources of contamination with Total Petroleum Hydrocarbons
in soil are related to exploration, production, storage, transportation, distribution and
disposal of fuels, such as biodiesel. Hence, this study examined the ability of
bioremediation of soil contaminated with biodiesel and glycerol using mixed culture (C1)
from site contaminated by petroleum products. The culture was adapted in two stages
of adaptation.
In the first stage to the liquid medium and later in contaminated soil contaminated
by biodiesel and glycerol, called R01. For adaptation of microorganisms to the
contaminated soil, the reactor R01 contained 1.5 kg of soil in which the relationship C:
N: P-100 has been corrected: 10:1, as well as pH, humidity and oxygenation of the soil.
It was used the technique bio augmentation with four reactors called R1, R2, R3 and
R4.
In every of these reactors was used a total of 400g of contaminated soil with
percentages of 15 %, 20 %, 25 % and 30 % by weight of soil conforming to fractions
removed from R01 source. The same operating procedures working in R01 were
applied in monitoring the other four reactors for 111 d. The results indicate that after 111
days there was a reduction of Total Petroleum Hydrocarbons percentage 21, 31, 43 and
51 in reactors (Lemos, et al., 2013).
In this review scientist begain to overview polymers could be intended to develop
vulnerable to bacterial occurrence, creation them degradable in a microbial vigorous
environment. Biodegradable plastics released the mode for current attentions of waste
management factors then the resources are intended to degrade in attendance of
environmental situations. However, the production cost of PHA is quite high compared
with that of synthetic non-biodegradable, and so great effort has been recently made for
making this process economically more feasible, for example, by mthe modifying
substrate from glucose to other renewable resources. The formation of PHA in crop
plants can be considered as a prominent alternative for the large scale and low cost
production of this synthetic polymer.
By changing the carbon source and bacterial strains for biopolymer production
with properties ranging from hard and brittle plastics to elastic polymers is one method
of cost reduction. However, bio plastics can have its own environmental effects, based
on the way it is synthesize. Therefore there is an serious necessity to progress active
microbes and their produces to control this worldwide problem with plastics
(Maheshwari, et al., 2013).
In this review show that, there has remained a remakable hike in attention in
biodegradable materials for use in farming movement, packing of substantial, medicine,
and other altered zones. It means that there is interest increase in biodegradable
polymer materials known as bio composites. Number scientist working on modifying and
designing traditional material of plastic. This type of material is cant hazards to
environment. Many of the biological resources may be contain into decomposable
polymers resources, with the best common existence starch and thin thread to take out
from different types of plants. The result is that decomposable plastic resources will
decrease the necessity for artificial polymer manufacture at a cheap rate, so departure a
progressive outcome on both environment and economy. This research paper is
intention to arrange for a small summary of effort that is under way in the zone of
decomposable polymer study and improvement, the technical reason behind these
resources, areas in which this research is presence implemented (Kumar, et al., 2011).
This research paper study objective is to isolate phenol degrading microbes from
the area of Lonar Lake (Buldhana, Maharashtra), India, its large group of organic
compound means pH 10.5, from 4 the matter that settle to bottom and water samples
of Lonar Lake, a bacteria Pseudomonas stutzeri was isolated and identified based on
morphological, cultural, biochemical possessions and 16S rRNA genetic material
connected series.
The test result implies that the isolate take out nearly about 87% carbolic acid in
the peptone water carbolic acid medium at research laboratory level. Thus, the
alkaliphilic bacterium, Pseudomonas stutzeri, confirming an bordering Lonar lake
bacterium, which might consequently be commercially success for bioremediation of
carbolic acid, a most important poisonous pollutant in industrial waste sewages
released from Industries (Tambekar, et al., 2012).
The analysis defines decomposable developments of xenobiotics such as
aromatic combinations, polymers like PVA, polyesters, polyethylene, and nylon, and
polymer blends like Starch/Polyethylene, Starch/Polyester, and Starch/PVA.
Furthermore, these study contains data around decomposable plastics like
combinations of artificial plastics and materials that are easy degradable by bacteria
which are artificially modified starch, starch-polymer compounds, thermoplastic starch,
and decomposable filling constituents, artificial resources with clusters vulnerable to
hydrolytic bacterial attack (polycaprolactone), and biopolyesters (poly-β-
hydroxyalkanoates).
The manufacture of such caring of material and presenting it to the bazaar is
significant for the regular ecofriendly. It may effect in lowering the capacity of substantial
waste (Leja, et al., 2010).
The PHB accumulate in the designated isolate was definite by the process of
staining with Sudan Black and Nile Blue Sulphate stain then done the fluorescent
microscopy process. In the cell membrane accumulation of the PHB was found and the
optimal situations remained maintained.
The ideal incubation period was stable totwenty four hours, ideal pH was
continued at ordinary i.e. 7 and the optimum temperature for incubation was 300C.
Thereafter it was clearly definite the occurrence of intracellular PHB.
The particular bacteria can too produce seventy elements of polyphenol oxidase
organic chemical substance after period of sisteen hours of incubation in PHB
generating medium. The bacteria used in this research study can be measured as a
decent source of PHB and additional work is to be prepared to assess the opportunity of
up exciting the method (Nair, 2013).
This review describes Scientists and discovered three species of marine bacteria
which have established their ability to degrade polyethylene, which are non-
biodegradable substances that stay in the surroundings for an long period of interval.
According to the CPCB, India creates nearly 56 lakh tonnes of polymer waste each year
by only 60% of it being recycled and reused. The remaining 40% causes not just
littering but is hazardous to freshwater, marine and terrestrial ecosystems. Sixty species
of bacteria were collected and the bacteria were cultured in the laboratory and tested for
their capability to decompose minor samples of polyethylene taken from plastic bags.
The efficacy of the microbes to decompose plastic was also determined by
quantifying growth and metabolic activity on the polyethylene surface. The loss in dry
weight of polyethylene films used was found to be 1%, 1.5% and 1.75% after 30 days of
incubation with the K. palustris, B. pumilus and B. subtilis isolates respectively,
indicating B. subtilis to be the most effective among the three bacteria (Herlekar,
2014).
This research paper studied on toluene which commonly occurs in petroleum and
its linked products each focused consideration due to these unfavourable effects on
health and cancer-causing potential. Smimilarly microbes are clever to consume
petroleum hydrocarbon as carbon sources of energy, they can be utilized for the
method of bioremediation applications. This study was to separate toluene degrading
microbes from waste water as well as sea water. The creation of exopolysaccharide,
biosurfactant and peroxidase enzymes like laccase and catalase were examined to
conclude the effect of them on toluene degradation by the microorganisms.
For screening and separating toluene degrading bacteria, dirty seawater and
wastewater samples were added to toluene having mineral media. The biological and
molecular features of the separates were then studied.
Bacillus and Sporosacina species were ability to degrade the toluene and this
are isolatred from the samples of sea water. (Abari, 2012).
In this research paper study done on styrene and bacteria were isolated from the
bed of an experimental bio filter purifying exhaust the gases. In order to isolate the
bacteria styrene was introduce into the medium. The study also describes the ability of
isolated bacteria strains to degrade styrene. The active
bacterial isolated for styrene are Streptomyces halstedii, Bacillus megaterium,
Sphingobacterium spiritivorum, Bacillus cerus. The efficacy of styrene biodegradation
was up to 100 % and the rate was about 23 g m-3h-1 (Przybulewska1, et al., 2006).
In this study research carried out on polyethylene type of plastic, and isolation of
beneficial microorganism for biodegradation in laboratory condition. The isolated and
identified microorganisms are Aspergillus terreus Gr., Aspergillus wentii Gr., Emericella
nidulans, Pseudomonas sp. and Streptomyces sp., on different biodegradable
polyethylene indicated biodegradability in terms of weight loss of plastic in liquid with
biofilm formation on plastic strips. It was also observed that bacteria remained more
active as compared to fungi in biodegradation process.
Amylase production by confirmed microorganisms showed that A.terreus
produced maximum amylase followed by E.nidulans, A.wentii, Pseudomonas sp. and
Streptomyces sp.
Bio-efficacy of microorganisms against different BD PE in pots specified that
colonization of plastic was not found up to 3 month interval by all of them but E.nidulans
found to colonizing IPCL plastic and A.wentii colonizing Israel plastic at 6 month interval
(Poonam, et al., 2013).
In this review the seperation, categorization and outline of definite microbes in
petrol derived oil biodegradation capacity studies are significant once expressing the
accurate bioremediation approach. Colorimetric method was carried in repetition for the
biodegradation study. Bacillus subtillus species were used for the practice of
biodegradation of oil. Colorimetric methodology used to oils biodegradation enhances
certain conversation.
Therefore, this one helps the expansion of recent methods in the process of
water management. From this data, the self acting lubricant oils biodegradation take
place due to hydrocarbons and carbon-based plastic are used as metabolic substrates
by microbes.
So similarly, little ubricant oil compounds like cyclic alkanes are not decompose by
single microbe. Therefore, a microbes associated to a identified possibly oil
metabolizing bacteria likes B. subtilis will also do an majored role in decompose these
complexes . so, a Bacillus subtilis shows superior oil biodegradation (Bidoia, et al.,
2010).
This review describes the microbes like microbes are imparted in the degradation
of both natural and synthetic polymers. The decompose of biopolymer runs vigorously in
various soil situations giving to their properties and the microbes liable for the
degradation.
They varies from one additional and have their individual optimum growing
situations in the soil. Plastics having own probable substrates for microobes. Therefore
is perfect that the biodegradation rate is identical fast in the event of subsurface burial
for all films.
In the experiment, Bi-OPL since to be to have a great opposition to soil types. Bi-
OPL resources to obtain as compensation from the soil verified very less degradation,
shown by lesser variation in flexible strength, mass injuries and with determined 26%
reduction in elongation at break. A large degradation was seen for Chitosan films.
At the end of tests, Chitosan films were fully degraded at all of soil types and together of
superficial and subsurface locations. The starch confined in Mater Bi samples was
degraded after 60 days with 4% weight losses and lead to 3% detected losses in flexible
strength.
Weight losses of Ecoflex and Bioflex were greater extent afterward period of 3
months other than 30% than before 5 to 10%. The tensile strength of both Ecoflex and
Bioflex films reduced by about 4% and 3% by Week 12 in sample of both soils
correspondingly.
Around other than 40% of the extention capacity of the films was lost by month 3
in either of soil types. The reduction of %E in both films was marginally higher in loamy
and loamy sand soil than in sandy soil. All together, it can decided that the decoposition
of all bioplastic films under the study was higher as compared in subsurface than
superficial places. (Mostafa, et al., 2010).
The current review study was showed for the microbial degradation of LDPE film
in natural conditions using mixture of potential polymer degrading groups. For this
purpose, the talc based formulation of bacterial consortia was inoculated into soil with
LDPE film for the period of three months. This study demonstrates that the use of the
combination of potential bacterial strains in the form of consortia accelerated the
degradation of polymer film, buried in soil in landfills, as revealed by the structural,
morphological and thermal changes in the treated LDPE.
The current analysis may be a step towards large scale application of used LDPE
degrading consortia in carrier based formulations. Supplementary, various queries
persist to be unanswered with the ratio and fullness of biodegradation and increasing
time for decomposition under various ecofriendly situations (Negi, et al., 2012).
In this research article scientist suggest that the plastic can be degraded with the
help of biological agents and microbial enzymes. The process of biodegradation of
most organic chemical substance is greater in fungi than in case of bacteria. The
microbes population and the elements affecting the creation of organic chemical
substance, a short review is showed on numerous specific cluster of organic chemical
substance. This article indicates that the one of the best effective technique to handle
these complications is enzymatic biodegradation of plastic that will improve the rate of
biodegradation (Bhardwaj, et al., 2012).
Many methods for attaining further reliable degradation are required. But, very
limited microbes elaborate in the procedure of degradation must still now from
seperated the surroundings.
For conclude the usual ratio of biodegradation of decomposable plastic, the
incubated mulch film made from PBSA (two × two cm squares) in soil found from fields.
After four weeks of incubation at 25°C, the film had decomposed by 28.2 percent at a
soil humidity content of 60 percent, and 9.1 percent at a humidity content of 50 percent.
Around 5 and 6 weeks, the degradation rates at a soil moisture content of 50 percent
are 19.8 percent and 48.9 percent.
In this review that Pseudozyma species which are easily seperated from plant
surfaces, showed higher degradation process on films. (Kitamoto, et al., 2011).
The object of this study is to determine the role of biofilm formation and
colonization of bacteria during the decomposition of polymer films by microbes.
These paper two active strains were isolated and known as Bacillus
amyloliquefaciens. The cell surface hydrophobicity behavior of those strains was
determined.
The bacteria were treatment to colonize on polymer which was evaluated and the
formation of biofilm was counted. The bacterial biofilm was visualized by scanning
electron microscope (SEM).
During the study it was found that BSM-2 strain have the maximum capability to
colonize, form biofilm on the inert LDPE films and facilitated maximum polymer
degradation compared to prototype BSM-1. BSM-2 also exhibited higher cell surface
hydrophobicity of 45.23% compared to strain BSM-1. The present result suggests that
determination of cell surface hydrophobicity is important to decide the potentiality of
strain for LDPE biodegradation (Das, et al., 2013).
The isolation of bacteria nutrient agar medium and Tryptic Soy Broth medium
were used and incubated for five days. Isolates were resulted towards examined 1
month of incubation in liquid culture method at 37oC with agitation 130 rpm.
The biodegradation of polyethylene was resulted by isolate of 22 Tryptic Soy
Broth were 17% in 1 month and bacterial count is 3.08 x 106. The bacterial types
observed related with the decomposing resources were recognized as gram positive
bacteria, the shape was rod, have no spore (Mahdiyah, et al., 2012).
This review study was done on the isolation of the fungal strain having ability to
adhere and degrade the cellulose blended polyvinyl chloride films. The films were
buried in the soil added mixed with municipal sewage waste for six months. Two fungal
strains were isolated and showed adherence on the surface of the Cellulose blended
PVC film. The strain identified as Phanerochaete chyrosporium, was more efficient than
the other in de-grading cellulose blended PVC films and was selected for further
studies.
The biodegradability of plastics was determined by graphic changes in the
polymer, plate assay and Carbon dioxide production. The chemical changes like
appearance and shortening of peaks using FTIR also confirmed the degradability of the
plastic (Ali, et al., 2009).
The current study reports on decomposition of starch attached polymer,
effectively produced by branch copolymerization process consuming benzoyl peroxide
as the radical inventor. Biodegradation research of the branched polymer were done out
by soil burial test. After a specified number of day’s micro examination of the earth
having the samples was done. These colonies raised of microbes with rising amount of
generations were detected.
Hydrolysis of goods of the sample, taken out from the earth after a definite
number of days also verified the results, viewing never stoping reduced weight through
to become greater number of days. Result of degradation of the attached samples
buried in soil and urea enriched soil on the progress of plants was examined and it was
observed that the plants produce generally in the soil with the attached material (Kaur,
et al., 2010).
In this work, firstly the actual state of research on biodegradation and
biodegradability of polymers was presented. It was shown that there are major
differences between freshwater tests and those in marine tests. The potential of
biodegradation freshwater and marine tests was shown for the first time systematically
for the group of poly(ethylene glycols) ranging from 200 to almost 60’000 g·mol-1.
It was observed that detailed parameters such as molecular or structural
properties of the polymers do have effect on the biodegradation in different
environments such as an effect by molecular weight, number of hetero atoms in the
chain, specific behaviour of groups that hydrolyse but do not biodegrade.
When comparing data obtained from biodegradation tests using different
measurement techniques such as biological oxygen demand determination, dissolved
carbon and inorganic carbon measurement, it can be seen that the treatment of the
inoculum prior to the test and the mineral medium had some influence on the quality of
the results.
It was observed that the TOC content of the inoculum suspension must be
reduced espe-cially when using biological oxygen demand as the measured parameter
of choice. But also for dissolved carbon and inorganic carbon determination it is useful.
Especially the oxygen measurement (BOD) is very sensitive and may be
influenced a lot through biodegradation of small amounts of carbon.
Second, biodegradation of polymers needs to be further researched and methods need
to be developed and enhanced especially to qualitatively and quantitatively analyze
different polymers in environmental matrices and also determine microorganism
communities more easily.
It also enhanced biodegradation tests should be developed that use abiotic
ageing procedures prior to biodegradation experiments to provide more rapid
techniques along standard tests. Further on it would be appropriate to find small scale
tests that can be done with- out much lab space as pre-screening tests or even
simulation tests in a small scale system. Today sensors are available to measure
parameters online in closed test systems without any connection to cables and lines.
Also it has been demonstrated that microbial activity can be measured using electronic
equipment.
Finally, the results described and discussed in this work have given one of the
first systematic impressions in the biodegradation process of synthetic polymers in the
aquatic environment with a focus of marine environ-ment. They show how difficult an
approach to investigate biodegradation correctly is especially for the aquatic
environment. However, this is a serious topic that requires much more kindness but
certainly in a carefully directed and planned way because of the political and social
discussion going on today (Jan Eubeler, 2010).
The main object of this review was the expansion of plant established
biodegradable plastics.
White biotechnology has too effective in synthesizing biodegradable plastic. In
adding to these techniques of developing plant resources for decoposable plastic
creation, the current analysis also reports the improvements in manufacturing new
plastics.
So, there is a stigma related with transgenic plants, predominantly food crops,
plant generated biodegradable plastic, formed as cost added co products, or,
frommarginal terrestrial, yields like as switchgrass (Panicum virgatum L.), have the
prospective to developed feasible substitutions to petroleum built polymers and an
biologically friendly and carbon neutral basis of plastic (Mooney, 2009).
This review indicates the decoposition of a profitable biologically degradable
polymer was examined in two phases. First was abiotic oxidation in an air oven to
rouse the result of the degradable surroundings, and in occurrence of designated
microbes.
After the biofilm creation fluorescence microscopy were done. It also has realized
that bacterial progress arose on the occurrence of polymer samples that had been
density moulded to heavy segments but had not been purposely peroxidase.
The Molecular enlargement and increase of molecular weight circulation arose
post biodegradation heating in air at 60°C but not at ambient temperatures but
colonization of microbes arose on all samples.
Eating away of the film surface was detected in the neighborhood of the
microbes and the decreased of oxidation produces in the surface of the plastic film
was counted by FTIR capacities and was originate to be related with the creation of
protein and polysaccharides, added to the progress of the microbes (Bonhomme, et
al., 2003).
In this review the plastics which were used for study are polyvinyl alcohol, nylon
and polyethylene, Sesbania and guar gum, polyester polyurethane, polyethylenes,
polyvinyl chloride, polyesters, polyhydroxyalkanoates, polylcaprolactone, polylactic acid,
polyurethane, etc.
For the degradation of plastic different microorganisms were used, the microbes
which used the carbon as source for their growth or for energy production and degrade
the hydrocarbon present in the plastics.
few of the microbes elaborate were Staphylococcus, Bacillus, Phanerochaete
chyrosporium, Penicillium frequentans, Bacillus mycoides, Pseudomonas spp.,
Xanthomonas spp., Flavobacterium spp., Micrococci, Streptococcus, Pseudomonas
putidaesVM15A, Streptomyces spp., Aspergillus spp.
The outcomes are definite by the weight, flexible strength and decline in
thickness in few cases, molecular weight circulation, and fragility. The study is beneficial
for the molecular design of biodegradable plastics and for the molecular development
and propagation of degradation enzymes and microorganisms. It deduced that this
studies degradation of plastic polymer can be prepared still active (Gnanavel, et al.,
2013).
In this research article work done on the polyethylene type of plastics and the
most difficult polymers in this favor is probably polyethylene, which is one of the
greatest inert artificial plastic and is strong to bacterial attack. They evident for the
degradation of polythene films in the natural environment is slow and therefore,
possesses a serious environmental concern. A new generation of environmental friendly
polyethylene containing a minimum of 9% starch and pro-oxident additives are strongly
recommended for consumption as their degradation in natural surroundings is greatly
earlier.
Hence it is showed that the usage of plastics is harmless as it can be degraded
in the soil. The outcomes are definite by the weight, flexible strength and reduction in
thickness in certain circumstances, molecular weight circulation, and brittleness.
The HDPE polymers are viewing opposition to earth situations than LDPE.
Present research is beneficial for the evaluation of the oxo-degradable response of a
polyethylene film sample (Gnanavel, et al., 2014).
In this study examined the capability of microbes existing in the residue sample
to damage these hydrocarbons, crude oil in specific, so that dirty soils and water can be
treated consuming means of bacteria. Residues samples were assemble when in a
month for a period of twelve months from zone nearby stream and isolate the microbes
for hydro carbon degradation. Out of 15 isolates were nominated for the determination
of crude oil decomposition, these bacteria are isolated and separated and for separation
and cultivation BH media were used, 1% crude oil used as a single carbon basis of
energy.
Three types of bacterial species were identified like Bacillus subtilis,
Pseudomonas aeruginosa and Pseudomonas putida. The maximum decomposition rate
55 percent was noted by Pseudomonas aeruginosa .
Though, additional measure studies as suitably essential to be passed
out raising the decomposing capability and constancy of the crude oil decomposing
separate and its practice as a profitable strain (Mamitha, et al., 2013).
Pure shake flask culture were used for examine the degradable plastic.
(Lee, et al., 1991).
In this study done degradation of plastic by using microbes and estimated the
weight loss and observed the film surface of SEM. At the time of experiment Isolation,
separation and multiplication of microbes and identified the species Aspergillus niger
105 .
After incubation of microbes, the weight loss of plastic is not significant because
high resistance percentage of polyethylene. The
Aspergillus niger 105 capable for produces a thin filament on polymer surface.
Weight loss of plastic suggest that the slow process of Polyethylene biodegradation
(Constantin, et al., 2012).
In this review polyacrylamide-degradation was observed. There are two bacterial
strains were isolated, separated and multiplied. The identified bacterial strains are
Bacillus sphaericus and Acinetobacter species correspondingly.
At the time of experimental work polyacrylamide as single carbon and nitrogen
bases of both species.
The results were B. sphaericus No. 2 and A. species No. 11 decreased by 16
perceent and 19 percent of the earlier polyacrylamide concentration, respectively.
Optimum pH and temperature in growth of Acinetobacter species No. 11 were 8.0 and
37°C, respectively. After 14 days improvement of A. species No. 11, the ordinary
molecular weight of polyacrylamide has been moved from 2.3 x 106 to 0.5 x 106
(Matsuoka, et al., 2002).
Present study on de of starch decoposition afted polymer, effectively produced
by branch copolymerization technique consuming benzoyl peroxide as the major
inventor.
Soil burial test were determine for the Biodegradation of polyethylene.
Observation and measurement of weight loss of polyethylene were done for number of
days. After the experiment microorganism are isolated separated and multiplied and
biochemical tests were performed. The Rhizobium meliloti species were identified.
The degradation was further confirmed by carrying out the physical
characterization of the control samples and the treated samples by means of scanning
electron microscope (SEM) and thermo gravimetric analysis (TGA). Hydrolysis of
grafted samples, removed obtainable from the earth afterward a quantified amount of
days also supported in the results, illuminating endless loss of weight with growing
amount of days (Gautam, et al., 2013).
In this review biodegradation of lignin was studied. Composting method is usual
treatment for sewage waste. Composte house waste comprises, organized with
vegetable waste, variable quantities of papers and boards.
The house hold waste contains Paper is prepared of lignocellulose and it can
comprise up to rwenty percent of lignin. It means that lignin degradation was also
necessary.
Nevertheless, mixture of microorganisms were used for the biodegradation of
lignin, therefore for lignin decoposition by white rot fungi has been widely studied in
recent years. Organic matter is transformed to carbon dioxide, humus, and heat by
compost microbes.
It was also presumed those humus is made mostly from lignin. Thus, lignin is not
totally at all produced in mine throughout degradation. The suitable temperatures
originate through the thermophilic stage are required for fast decomposition of
lignocellulose.
The Complex organic compounds like lignin are mainly decomposed by microbes
like thermophilic microfungi and actinomycetes. The optimum temperature for
thermophilic fungi is 40 plus or minus 50°C which is too the optimum temperature for
lignin degradation in compost (Tuomela, et al., 2000).
In this review microorganisms were separated from soil samples were separated
for their capability to destroy biodegradable polymer. In the present study, the best lively
strain S 32 was appropriate as the best strain for demeaning these polymers.
From its phenotype and hereditary appearances of S-32 wasfound closely
related to Pseudomonas aeruginosa which could be able to degrade both solid and
emulsified poly butylene succinate co adipate (PBSA) (Hemashenpagam, et al., 2013).
During the present study, reduction in COD and colour of methyl red was on
account of its degradation by microorganisms in the bioreactors. Both species of
bacterial and fungal species of the bioreactors have been found to decolorize dyes in
their in vitro cultures (Kumar, et al., 2006).
The isolates also grew on minimal medium containing only LDPE in the powdered
form as the carbon source even without any nitrogen source. We have also proved that
the LDPE can be totally degraded into carbon dioxide which brings us closer to the
fulfillment of the objective of isolating a micro-organism that can completely degrade the
recalcitrant polyethylene if the right conditions are provided (Sindujaa, 2011).
In this paper work done on Biodegradable materials, there has been aobvious
increase in interest. They are useful in packing, farming field, drug, and numerous
further parts. The Polymers is made up of the backbones of plasticmaterials, and are
continually being used in an increasing multirange of areas. Manymore scientists were
working on biodegradable material and that changing old-style resources to prepare
them more used friendly, and into planning different platic complexes from certainly
arising resources.
The starch and fiber removed from many kinds of plants and used for the
decomposition material. The confidence is that decomposable plastic resources will
decrease the essential for artificial plastic manufacture and thus decreasing toxic waste
at a cheaper rate, thus yeilding a optimistic result on both environmental and
economical (Kolybaba, et al., 2003).
In this review involve studies on the decoposition of polymers, and they are
depending on decomposing bacteria, degradation organic chemical substances and
their genetic factor and plastic arrangements for the purpose of decoposition.
The present study was valuable for the molecular planning of decomposable
synthetic plastics and for the molecular growth and propagation of decomposable
organic chemical substances and microorganisms. This study indicates that the
development process done in biotechnology for plastic waste management (Shimao,
2001).
In this research decomposition of triphenyl methane peroxides completed by
using microbes, actinomycetes, yeasts, and fungi. In this study biological treatment
processes are used for the experiments and they have many advantages over the
chemical and physical treatment processes such as opportunity of degradation of dye
molecules to CO2 and H2O and creation of a smaller amount of slurry in adding to being
ecologically approachable.
These clusters of dyes are toxic liable on the attentiveness used. Poisonousness
of triphenyl methane dyes is deliberated with admiration to dissimilar bacteria. Some
aspects of biodegradative products of this cluster of dyes are also stated (Azmi, et al.,
1998).
In this review study done on isolation of plastic degrading fungi in Jordan habitat.
The plastic pieces samples are collected from campus area and at least 70 fungal
isolates recovered from soil. In this different samples 35 isolates showed varied
potential to degrade polyester-polyurethane (PS-PUR) and Six of these isolates are
selected for the experimental studies. The six species Fusarium solani, Alternaria
solani, Spicaria spp., Aspergillus fumigatus, Aspergillus terreus, and Aspergillus flavus
were selected on the basis of their growth rates. At the experiment basal salt media
amended with PS-PUR as the single basis of carbon were used. For separation of fungi
three dissimilar methods were used. There are 1) direct plating, 2) clear zone in a 2-
layered agar media, and 3) liquid shaking culture.
The weight loss of Plastic were measured and best results are obtained the
species Fusarium solani. The petri dish test method revealed a maximum degradation
activity achieved by the isolate Aspergillus flavus, which caused 94% loss in weight of
PS-PUR pieces. nevertheless, only 4 isolates (Fusarium solani, Spicaria spp., Alternaria
solani, and Aspergillus flavus) yielded positive results of biodegradation, indicated by
clear zones created due to PS-PUR hydrolysis in 2-layered agar culture plate media.
Out of the 6 fungal isolates reported here, 2 novel organisms have not been
previously reported, Alternaria solani and Spicaria species.
Overall, these findings helped identify predominant as well as novel fungi in Jordanian
habitats that play a key role in PS-PUR degradation (Ibrahim, et al., 2011)
This review study on, a procedure founded method in landfill planning and
purpose has been established, means bioreactor landfill were used. For the experiment
moisture content, recycling nutrients and spore of microorganisms in bioreactor landfill
maintained to increase speed of biodegradation of the carbon-based wastes
(Chiemchaisri, et al., 2004) .
There are various types of plastics, in this research biodegradable plastic low
density polyethylene is involved for the study. The scientists have developed some
biodegradable plastics in answer to require for waste free plastic products.
Decoposable polymer can be degraded by microbes or organic chemical
substance by means of break down the molecular linkage. LDPE type of plastic is one
of the polymers that are up till date nearly impossible to be degraded fully in faster way,
therefore in this study finding, fungal strains for LDPE degradation. Current research
five fungal strains were isolated from soil buried LDPE films and showed attachment
with it. Out of five, four were identified as Aspergillus species and the rest one was
Fusarium species. Effectiveness of the microorganisms in polymer degradation was
investigated by weight reduction, change in pH, CO2 evolution test over a period of 60 d
at 33.3 °C.
The fungal colonization was visualized by scanning electron microscope (SEM)
whereas the surface chemical changes were confirmed by Fourier transform infrared
spectroscopy (FTIR). As all the isolated fungi showed the good biodegradation results
for polymer Degradation Das, et al., 2014.
The work is to focus on the esterase manufacture of V. fischeri isolated from
squid and on the purification and partial characterization of its esterase. The results of
the effect on various inhib bitors on the activity of the esterase. Except NaCl, CaCl2, this
showed no effect on enzyme activity.
In this study the SDS was highly favored the activity of esterase (133%). The
esterase enzyme activity was not inhibited by the EDTA. It produced 67% of the activity
in the occurrence of EDTA.
In this review In. situ treatment of hazardous waste spills, leaking underground
tanks, and landfills has been focused. The results of most field testing that has been
accomplished in this area have never been published. Presented here is a discussion of
a tanker truck spill of styrene monomer and its ultimate removal by means of in situ
bioreclamation. A tank truck containing 5000 gallons (18 927 1)of styrene overturned on
a rural highway in Ohio spilling over 90 percent of its contents onto the ground. Area
soils consisting predominantly of sandy silts with moderate permeability (5-10 f/s or 1.5-
3 m/s) were quickly saturated to a depth of 3 feet (0.914 m). Approximately 400 gallons
(1514 1) of styrene was recovered at the surface, leaving over 4500 gallons (17 034 1)
to be degraded biologically from soils and ground water.
A bench-scale testing program, which utilized microorganisms obtained from an
industrial wastewater lagoon as an inoculum for styrene in soils and shallow ground
water, included a series of injection and recovery wells and above grade secondary
biological treatment within suspended growth reactors. A 90 percent reduction in
styrene was achieved within the first 10 weeks of operation. Styrene concentrations
exceeding 1000 ppm were reduced to less that 100 ppb over the 24 week
lifespan of the project (Kuhlmeier, 1989).
In the study, decoposition of polythene bag and plastic cup were examined forn
two, four and six month of incubation in liquid culture method.
Therefore it indicated that the Streptomyces species possess heigher possible to
reduce polythene and Plastic cup as compared to bacteria and fungi (Usha, et al.,
2009).
This paper study indicates that Brevundimonas diminuta, a member of the
Pseudomonadaceae family, is able to release into the culture medium two
metalloproteases with molecular masses of 50 kDa and 67 kDa. By means of a SDS-
PAGE-gelatin analysis, cell-associated proteases of 50 kDa, 67 kDa and 80 kDa were
detected. This review findings point to the possibility that the 50 kDa cellular and
extracellular proteases are different enzymes.
The cell-associated enzyme hydrolysed gelatin only, but the extracellular one
also displayed proteolytic activity with casein and hemoglobin at pH 5.5 and 10.0. The
67 kDa protease showed the same pattern of degradation of substrates, being able to
hydrolyse casein, gelatin and hemoglobin, and probably being released to culture
medium.
In addition, extracellular metalloproteases have been shown to contribute to the
bacterial pathogenesis of P. aeruginosa. In the growth conditions employed in this
study, the proteases were secreted following a 72 h interval. The production of these
enzymes is heterogenous in Pseudomonas spp. It has been described that distinct
amounts of enzymes are detected in different strains of P. aeruginosa.
The effect of metal chelators on Brevundimonas diminuta extracellular proteolytic
activity suggests that these enzymes are calcium activated zinc-metalloproteases. The
loss of activity in the presence of EGTA, which has affinity for calcium, is probably due
to the capture of Ca+2 ions that are critical to the tertiary structure of the protein,
resulting in an enzyme more susceptible to autoproteolysis and to difficulties in
refolding. Previous reports showed that P. aeruginosa alkaline protease contains one
Zn+2 atoms in the catalytic center and requires several Ca+2
ions for stabilization of its folding. The extracellular metalloproteases described in this
work are probably involved in the nutrition(Chaia, et al., 2000).
This review found that the newly moderate halophilic strain LY5 producing
extracellular esterase was isolated and identified.
The enzyme was highly active against p-nitrophenyl esters with acyl chain
lengths from C2 to C10, indicating an esterase activity. Enzyme purification was carried
out by combination of 80% ammonium sulphate precipitation, diethylaminoethyl
(DEAE)-cellulose ion exchange and Sephacryl S-100 gel filtration chromatography
method.
The molecular mass of the esterase enzyme was detected to be 96 kDa by
sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE). The purified
enzyme were greatly active over wide series of temperature (30 to 90°C), pH (6.0 to
12.0) and NaCl concentration (0 to 20%), showing optimal activity at 50°C, pH 10.0 and
10 percent Nacl. The Complete obstruction of the esterase by phenylmethylsulfonyl
fluoride, phenylarsine oxide and diethyl pyrocarbonate indicated that serine, cysteine
and histidine residues were essential for its catalytic function. Moreover, it exhibited
remarkable stability near SDS and Triton X-100. Results from this research paper study
indicate that the extracellular esterase from Halobacillus sp. LY5 may have been
considerable potential for industrial application from the perspectives of its properties
(Li, et al., 2012).
The study concluded that the presence of extracellular enzymes was responsible
for aggressive 10-day-heat-treated polyethylene of degradable plastics having 6%
starch and pro-oxidant (pro-oxidants are mixture of transition metals and lipids)
(Openwetware.org/images/4/48/Ming_Yon_proposal.doc).
Reported that the hypothesis was wrong because through-out this project
researcher learned that plastic did not break down. Using the different soils didnot make
any difference in the decomposition of plastics.
The temperature did make the plastic softer and no any change in the size of the
plastics. Plastics take hundreds of years to break down and decompose ( Karen, et al).
A study has been showed to decide the result of wood pyrolysis fuels on the
degradation of specific metal alloys and polymeric materials. They suggest that
martensitic steel SS422 can be used for pyrolysis oils at ambient temperatures and
homogeneous blended fiels. The addition of halogen and styrene groups in polymer
structures can improve resistances of polymers to the pyrolysis fiels. Elastomers with
saturated fluorine group are suitable for use with al1 fuels (Li, 2001)
The focus of the studies was to isolate, screen and select the most efficient
microorganisms capable of degradation of chlorpyriphos insecticide. The efficient
bacterial strain was further immobilized in calcium alginate beads to enhance
degradation. The most promising degrading bacteria were used to bioaugment the
chlorpyriphos polluted soil for its bioremediation.
As many as 32 representative microorganisms were isolated from the chlorpyriphos
enriched soil samples, which were proficient as growing on chlorpyriphos as a sole
carbon source. Out of these, 28 were bacteria, 2 were fungi and 2 were algae. Out of 28
bacteria, 13 grew on mineral agar medium and in broth medium having 100 ppm
chlorpyriphos as the only carbon source.
All the 28 microbial separates were partitioned verified for their capability to
degrade chlorpyriphos at 50 ppm concentration by estimating the amount of chloride
released. The strain JA15 resulted in the highest chloride release followed by JA8
strain. There was only a slight rises in the release of chloride by supplementing the
medium with additional carbon bases such as glucose, succinic acid and maltose @ 1
g/l. and, the rate of biodegradation of chlorpyriphos was marginally improved due to
glucose addition.
Strains JA15 and JA8 were found most efficient in degrading chlorpyriphos (98%
and 93% respectively) and hence selected for further studies. On the origin of
morphological and organic tests, it was tentatively recognised as Pseudomonas sp and
Enterobacter sp. respectively. In order to bioremediate waste water containing
chlorpyriphos, Pseudomonas JA15 strain was immobilized in calcium alginate beads
and the beads packed into a column for continuous operation. Complete degradation
was achieved in 120 hours in the first charge and 100 hours in the second charge. Thin
layer chromatographic analysis revealed disappearance of chlorpyriphos at 5 DAI and
appearance of an unknown metabolite having the Rf value in the range 0.15-0.19 by all
the isolates at 8 DAI.
The enzyme involved in chlorpyriphos degradation by Pseudomonas JA15
isolate was found to be extracellular and heat sensitive. Soil incubation studies revealed
that chlorpyriphos excerted a negative effect on germination, plant growth and biomass
of cowpea plants. The phytotoxic effects were counteracted by inoculation with the
promising degrading strains Pseudomonas JA15 and Enterobacter JA8 individually and
in combination.The population of different groups of microorganisms i.e., bacteria, fungi
and actinomycetes in chlorpyriphos spiked soil were severely declined throughout the
incubation period. However, they were increased due to the bioaugmentation with the
degrading strains singly or dually. The people of chlorpyriphos degrading bacteria in the
polluted soil were also found to increase throughout the period of investigation due to
breakdown of the pesticide. The biodegradation of the pesticide by the introduced
strains either singly or dually was two times higher than that of the environmental
degradation by the native strains. The seed inoculation method could be suggested as
the method of delivering the strains for the bioremediation of chlorpyriphos
contaminated soil as cowpea root exudates supported growth and multiplication of the
strains (George, 2005).
In this review suggest that the plastic waste problems of disposal are occur
therefore selected the degradation of polyethylene. This study shows that polyethylene
degraded properly, if proper microorganisms are used.
In this study, degradable low density poly ethylene (LDPE) samples were
prepared by blending with maleic anhydride as compatibiliser and starch as hydrophilic
additive.
For the experiment of biodegradation the microorganisms Bacillus subtilis (strain
2414), Bacillus subtilis (strain 3401), Bacillus cereus (strain 1307), Bacillus firmus
(strain 488), Pseudomonas putida (strain 2467), Pseudomonas alkaligens (strain 493),
Streptomyces badius (strain 3025), Streptomyces setonii (strain 3756), and Bacillus
macerans (strain 3348) are used in aqueous media and soil burial test.
This study measured the optical density, percentage of loss of weight and tensile
strength for the process biodegradation study.
In this study combine combination of microorganisms also used for the
degradation study and it’s indicate that the best results are obtained in combine
combination as compare to single strain experiment. A good degradation was observed
when there was a combination of Bacillus subtilis, Pseudomonas putida, Streptomyces
badius, and Bacillus firmus (Vigneswari, et al., 2009)
In this review plastic as well as municipal solid waste were degrade in vessel
Engineered Compost System. The solid waste were collected from Mariposa County, in
California (Greene).
In this research the biodegradation of synthetic polyesters such as
poly(tetramethylene adipate – co –tetramethylene terephthalate) (BTA copolyesters),
poly(ε-caprolactone) (PCL) andpolyteramethyleneadipate (SP 4/6) as well as the natural
copolyester poly(hydroxybutyrateco-hydroxyvalerate) (PHBV) was examined under
mesophilic conditions.
Firstly collect the samples from mature compost in laboratory. For the
experimental setup the isolation, separation and multiplication of the microorganism
were done in laboratory condition. The total 47 polyester degradingstrains 1 like 5 fungi,
24 actinomycetes, 8 general bacteria could be isolated using PCL and BTA 45:55
(Ecoflex) as substrate. Eight of themost effective polyester degrading strains were
selected and identified for further studies.
Distinct and enhanced degradation tests were recognised with these strains.
Theproduction of an inducible extracellular PCL hydrolase by strain E11 in liquid mineral
saltmedium was proofed and the hydrolase was characterized with regard to their
basicproperties.
The isolated polyesters degrading strains were classified according to their
specificity fortheir degradation substrate into two groups. From first group, selected
fungalstrains were identified as Arthrobotrys amerospora (EB1), Acremonium strictum
(EB14),Cladosporium herbarum (EB2T) and Gliocladium roseum (G1).
The second group they areable to degrade synthetic as well as natural
polyesters. These strains include fungi andactinomycetes. Selected fungal strains were
identified as Fusarium solani (EB10),Aspergillus fumigatus (EB19) and Gliocladium
roseum (G2). A selection of actinomycetesstrains were identified as Microbispora rosea
subsp. rosea (isolates E11 and Act3) andStreptomyces thermocarboxydus.PCL films
were degraded faster than BTA 45:55 (Ecoflex) by most isolates as it wasexpected from
results reported in the literature.
However, the strain Arthrobotrys amerospora(EB1) degraded the aromatic-
aliphatic copolyester BTA 45:55 (Ecoflex) faster than PCL (at25°C), indicating, that this
microorganism possibly has an enzyme system specialized on thespecific structure of
these copolyesters.
With 7 fungal strains, comparative degradation tests with BTA 45:55 (Ecoflex)
and PCL filmswere performed on agar plates at different temperatures (30°C,
25°C,15°C and 4°C). Adifferent behavior concerning the temperature dependence was
observed for these strains.While most of the isolates exhibited the most rapid
degradation at higher temperatures, threefungal strains showed also significant
degradation potential for the polymer films at 4°C.
These strains were identified as Fusarium solani (EB10), Cladosporium
herbarum (EB2T)and Acremonium strictum (EB14).The fungal strain Arthrobotrys
amerospora (EB1) was used to perform degradationexperiments with BTA 45:55
(Ecoflex) in a liquid mineral medium. Powder and nano-particlesof the copolyester could
be degraded up to 80% with this mesophilic strain within 12 weeks.Extracellular PCL
depolymerizing enzymatic activity in the supernatant of a culture from thestrain
Microbispora rosea subsp. rosea could be identified.It was shown that the extracellular
hydrolyase activity was induced by the presence of PCLand BTA-copolyester, while the
presence of additional carbon sources such as glucose or acomplex medium
suppressed enzyme formation. The concentrated crude PCL-hydrolasewas active
towards triglycerides (triacetin and triolein) and a wide range of syntheticpolyesters
(BTA copolyester, PCL and SP 4/6). In contrast the enzyme was not capable
todepolymerize the natural copolyester PHBV, although the organism itself degraded
bothtypes of polyesters (synthetic and natural polyesters).
The finding indicates the presence of at least two different extracellular enzymes
for thisstrain, probably a PHB depolymerase and a lipase. Lipases are known to be able
tohydrolyze synthetic polyesters such as PCL, while PHB depolymerases, which are
enzymesdesigned by nature to cleave ester bonds in natural PHB, usually are not able
to hydrolyzesynthetic polyesters.
The results obtained in this work provide useful information about the
degradation behaviour of polyester materials under mesophilic conditions, which is of
importance for occurrence for thepresentation of biodegradable plastics in agriculture. It
is obvious that a great number oforganisms exist, which are able to degrade various
polyesters even under mesophilic topsycryophilic situations where here fungi play an
important role.
In contrast it was establish inprevious investigations that at higher temperatures
(e.g. in compost) actinomycetes are thepredominant polyester degrading organisms.
The characteristics of a mesophilic extracellularenzyme isolated in this work leads to the
possibility that as already shown for thermophilicsituations, lipase – like enzyme are
responsible for the first step in the degradationprocedure (Deckwer, et al.,2003).
In this review indicate that for the production of PHA Waste obtained from
farming, dairy and oil industry etc. and is used as a raw material. In this process the
PHA are converted in PHB using microorganism & scahle up method.
The polymer resources like PHB will be decent bases of raw resouirces produce
of waste for the creation of polymer goods. The PHB decomposable plastic material will
be friendly for decomposition method. (Nayaket al., 2012).
In this review study done on linear low density polyethylene (LLDPE)
biodegradation. The number of test were done at the time of degradation experiment
such as the automated, current, FTIR, morphological (SEM), water immersion and melt
flow (MFI).
The decomposition research was passed out in shake culture flask having using
amylase generating microbes. The bacterias were seperated from marine benthic
surroundings and by means of soil burial test.
The result of low amounts of metal oxides and metal stearate as pro-oxidants in
LLDPE and in the LLDPE bio filler structures was identified by showing the samples to
uv radiation.
The effects display that the arrangement of bio filler and a pro oxidant hikes the
decomposition of linear low density polyethylene. The LLDPE increases the consistency
of the mixture consistents and the pro-oxidants improve the photodegradability of the
consistents mixtures.
The reprocessing ability studies on the partly decomposable LLDPE enclosing
biofillers and prooxidants suggest that the mixtures could be frequently processed
without change in automated possessions (Dilfi, 2011).
This study suggest that the nylon is one of the synthetic polymers which have
large applications in environment and they are found to be a hard plastic for
degradation.
In this study it is observed the viability of a fungus, Trametes versicolor NCIM
1086 for actively degrading synthetic polymer Nylon 6. The examination was passed out
by IR spectroscopy and automated methods. Nylon pieces were used in process of
fermentation broth which was incubated on a rotary shaker at temperature of 30oC and
90 rpm for period of 90 days.
The Nylon six was the single basis of nitrogen in the medium. The results of this
fungus shows that extensive degradation of Nylon 6. Flagging and cuttinhg of polyamide
bond have been established by flagging in IR band. The decomposition led to creation
of new efficient clusters CH3, CHO and COOH (Chonde, et al., 2012).
This research article study on aniline and its derivatives are one of an important
group of bio-environmental amino aromatic contaminants. Their presence in the
environment is a serious threat and danger for human health and other beings. These
combinations are very resistant against degrading.
The purpose of this study was isolation and identification of aniline degrading
bacteria from sediments of Kharg Island and investigation of their growth in presence of
this substrate. The samples were collected from Kharg Island sediments in spring and
summer season and bacterial collected from in laboratory condition and their isolation,
separation and multiplication were done.
Sample was added in mineral medium containing 400 mg/lit of aniline
concentration and aeration was done every day. In order to acute identification, usual
biochemical tests and PCR method were used. Bacterial number was counted in the
medium containing aniline and growth curve of bacteria was drawn on the basis of
obtained number.
The MIC test was done and the richness percentage of positive-gram bacteria
was more than the negative- gram bacteria. Aniline resistant bacteria to such as
Corynebacterium, Vibrio, Staphylococcus, Pseudoalteromonas, Marinobacter,
Pseudomonas, Photobacterium, Bacillus, and Salmonella were isolated and identified.
The average of bacteria’s number was 8.9×108 and 2.06×1010 CFU/ml in spring and
summer season respectively. The species Photobacterium damselae showed the
lowest rate of growth. Therefore the results showed that aniline biological degradation
by isolates was considerable and the Pseudoalteromonas arctica was selected in 2000
mg/lit MIC range as the more bacterium (Kafilzadeh, et al., 2013).
More than 90 percent of decomposition was detected in all conducts excluding
the one controled in four days. The origination of process decomposition in the divisions
are effluent greater than Patricks Bayou greater than Houston Ship Channel (Dorn, et
al., 1987).
This review shows high thickness polyethylene polymer (HDPE) is used in
various daily items like about as grocery bags, the highest customer element in the
world. When willing in landfills, this polymer takes over 100 years to decompose,
satisfying the landfill space, resulted the degradation of another elements, and
obstructive groundwater assembly .
In the study for the degradation process of high density polyethylene plastic the
species Phanerochaete chrysosporium fungus and the bacteria Pseudomonas putida
and Sphingomonas macrogoltabidus selected for the experimental study in natural
environment. High density polyethylene is the single carbon basis for the fungus and
bacteria.
The results indicate that the combine microbes results good as compare to the
specific microbes’ ratios of P. chrysosporium, P. putida, and S. macrogoltabidus have
been operated to greatest the decomposition of polymer pretreated with ultra violet rays
and current radioactivity. It was seen that the optimal mixture of microbes would
contain P. putida bacteria. In adding to the pretreatment of ultraviolet and current
radioactivity, a second pretreatment consuming manganese stearate and a lesser
current radioactivity was examined to recognize a pretreatment needing less current.
Three ratios (½ P. putida, ½ P. chrysosporium; ½ P. putida, ½ S. macrogoltabidus; ¼
P. putida, ½ S. macrogoltabidus, ¼ P. chrysosporium) from the three month lengthy
trials constantly decompose more than the other four fractions and the control.
An ANOVA trial run on the three month data specified that the decomposition by
the three ratios was dealing with facts substantial when tallyed to the control. Similarly,
manganese stearate pretreated polymer had an expressively greater degradation than
ultraviolet pretreated polymer, as shown by Kruskal Wallis tests for five of the seven
ratios. Using the greatest effective fractions and manganese stearate pretreatment
method, the degradation time of HDPE plastic could be changed from over hundred to
one 1 year (Broshkevitch, et al.).
In this study fungi isolated from soil samples were isolated, separated and
multiplication done for their capability to degrade biodegradable plastics. Strain
Alternariaporri, which is separated from soil samples and they show good results of
degradation.
Strain could degrade both solid as well as emulsified poly (butylene succinate co
adipate) .Identification of the fungal strains was done by using the 18srRNA sequence
analysis (Hemashenpagam, et al., 1991).
In this research article study, three test approaches were established to describe
the decomposition of polymer in oceanic surroundings. The main objective was to
summarise a test method to extent the corporeal and biotic decomposition in various
habitations where polymer waste can deposited when beleaguered in the ocean.
Earlier, study has intensive mostly on the situations unexpectedly by polymer
substances when variable in the ocean water (pelagic domain). Nevertheless, this is just
one of the probable habitations that polymer waste can be open. Waves and tides of
sea incline to carry up polymer waste on the beach, which is also a applicable habitat to
be studied. so, the decomposition of polymer matters suppressed under sand kept wet
with sea water has been monitored by changing the breakdown (visual disappearing) as
a imitation of the tidal zone.
Furthermost decomposable polymers have greater thicknesses than water and
also as a importance of polluting, they likely to fall below surface and place down on the
ocean ground. so, the destiny of polymer substances lying on the residue and then
monitoring the oxygen consumption (biodegradation). Also the result of a long coverage
to the ocean water, to stimulate the pelagic area, has been confirmed by determining
the deterioration of automated possessions.
The examination material was exposed to decompose total breakdown attained
with in less than nine months when suppressed in damp sand (simulation test of the
tidal zone), to miss automated possessions but still conserve honesty when it was
exposed to sea water in an aquarium, and significantly decompose 69 percent in 236
days (Tosin, et al., 2012).
For the degradation of PHB the samples were collected from the environment
and degraded with the help of specific strain of microorganisms. PHB is a thermoplastic
polyester manufactured by microbe Ralstonia eutropha and other bacteria as a form of
intracellular carbon and energy storing and accrued as additions in the cytoplasm of
these microbes.
Earth enclosing surroundings were the habitations from which the major amount
of fungal PHB decomposers was establish.
Another bacteria complicated in PHB decomposition were establish. A total
amount of thirtyone microbial strains out of sixty seven isolates displayed clear zones
on assay medium. (Lee, et al., 2005).
In this study soil was collected from three locations such as the local beech
forest, spruce forest and an industrial area. Control was maintained and control and
test microcosms having 150 ml soil were spiked with cypermethrin 0.4 mg/ml soil.
Cypermethrin residues were extracted on day seven and 14. Cyclohexane and
deionized water was utilized in multiple step extraction processes.
Samples of experiment were observed in a Gas Chromatograph (GC) method
with electron capture detector (ECD). Concentration values for the samples were
maximum for beech forest soil and minimum for the spruce forest and an industrial soil
types. Statistical variances in concentrations between control- and test-microcosms
were recorded for each soil type on day seven and 14 day were assessed with Mann
Whitney U tests.
Significant result was only established in the industrial 14 day group. The small
amounts of cypermethrin in the extracts could not only be attributed to a bacterial
degradation process. Used insecticide has a high bonding affinity for particles and is
sequestered in soil (Engblom).
In this review for the degradation study polyethylene type of plastics and isolated
species Rhodococcus ruber used and in the experimental study and polyethylene are
the sole carbon source.
The experiment done in liquid culture, C208 made a biofilm on the polyethylene
surface and degraded observed up to eight percent of the polyolefin within 30 days of
incubation. The results display that decomposition of C208 was greater than that of
three other isolates which were achieved from the same group but were found to be
comparitively less effective as compaired to C208 in the degradation of polyethylene.
The results of mineral oil, increases the biodegradation of polyethylene up to 50
percent. Fluorescein diacetate (FDA) hydrolysis and protein at ease examination were
utilised for experiment was done to observed the feasibility and biomass thickness of
the C208 biofilm on the polyethylene, correspondingly.
Both FDA action and protein content of the biofilm in a medium covering mineral
oil peaked 48 to 72 hours after inoculation and then reduced severely. This result
superficially reproduced fast consumption of the mineral oil following to the
polyethylene.
The residual biofilm population continual to multiply temperately and apparently
played a vital part in decomposition of the polyethylene. Fourier transform infrared
spectra of ultraviolet photooxidized polyethylene incubated with C208 showed that
decomposition was originated by consumption of the carbonyl filtrates formed in the
photooxidized polyethylene (Gilan, et al., 2004).
In this study for biodegradation, polyethylene type of plastics is selected for the
experiment. The present study aims to the manufacturing and isolation of PHB
(polyhydroxy buty rate), a biodegradable plastic, from agro-industrial waste products
(whey and date molasses) due to its high economic and industrial importance and
taking into consideration many points that lead to produce PHB on large scale.
In this study the species Lactobacillus acidophilus, Bacillus thuringiensis and
Bacillus subtilis selected for the biodegradtion of polyethylene. The production of
Lactobacillus acidophilus shows maximum production 0.412g/50ml after four days of
inoculation then Bacillus thuringiensis shows 0.367g/50ml production after four days of
incubation then Bacillus subtilis shows 0.337g/50ml production after 6 days of
incubation. The Lactobacillus acidophilus and Bacillus thuringiensis grown on medium
of Nutrient broth supplemented with molasses and Bacillus subtilis supplemented with
glucose, yeast extract and peptone.
The practical of this study includes screening study for the isolation was done
and to estimate the best environmental and physiological factors that lead to maximum
PHB production.
Under the optimized conditions eleven nutritional factors were examined for their
significance on PHB production. Maximum PHB output of 43.1 g/l produced by
Lactobacillus acidophilus was exposed by the statistical design, which signifies about
7.04 fold rise in PHB production.
Fed batch fermentation was carried out using the optimized fermentation medium
and PHB production has been increased to 27.5% as compared with batch closed
process. PHB was noticed by transmission electron microscopy and monitoring UV
spectra of the sample by scanning the samples between 220 and 300nm compared with
standard PHB.
Lactobacillus acidophilus can be used for PHB production on large industrial
scale, solving by this one of the problems of solid waste management (Hamieh, et al.,
2013).
Strains Phanerocheate chrysosporium and Aspergillus niger showed the
uppermost TOC elimination proportion of 32 percent and 21 percent respectively, before
addition of nutrient .
The Outcomes of investigational effort approved out explains that the fungi like
Phanerocheate chrysosporium and Aspergillus niger were capable of creating enzymes
at a quicker rate to degrade the substrate hydrocarbon and unconfined more CO2. So
these fungi can be consumed successfully as agents of decomposition in waste
recycling process and Bioremediation of oil polluted places (Maruthi, et al., 2013).
This review suggests that the defined areas of PU can decompose more freely in
added, polyester is measured to be additional liable to bacterial occurrence than
polyether. The hydrolysis of ester bonds in the polyester sectors of PU have been
exposed to happen through esterase movement.
The production of ammonia indicates that the attack does occurs. The number of
microorganism isolated from soil including bacteria and fungi. In these microbes which
bacteria and fungi are capable for degradation of polyurethane are selected for the
experiment.
The bacteria utililised in decomposition of PU is from the Pseudomonas species
cluster. The esterase enzymes accountable for PU decomposition were noticed to have
a great homology to group I lipases. Upon nucleotide sequencing of these ORFs, the
expected amino acid sequence confined a Gly-X -Ser-X-Gly motif distinguishing of
serine hydrolases. Parsimony analysis of the expected amino acid sequences for the
PueA, PueB, PudA, and PulA polyurethanase enzymes and related lipase enzymes
have been achieved.
Remarkably, it is seen the PUase enzymes do not form a particular group, but
perform to be dispersed between many pedigrees. This examination mentions that
PUase enzymes when more study done, have developed from lipases, and are not
resulting from a solitary basis. Knowledge supplementary about the pathways for
decomposition and the genes elaborate in PU decomposition is needed in emerging
either recombinant results or enriching for native PU mortifying microbes for
bioremediation (Howard, 2012).
This review study done on biodegradation of dydrocarbons and their survey
suggest that several compound of hydrogen and carbon dirtied surroundings are
considered by small or high temperatures, acidic or alkaline pH, high salt attentions, or
high pressure. The number of microbes are modified in hydrocarbon containing
environment and degradation observed.
The biodegradation compound of hydrogen and carbon, together with
aliphatic,varomatic, halogenated and nitrated complexes, has been exposed to happen
using different microbes in several exciting habitations. The decomposing of several
constituents of petroleum hydrocarbons has been stated in a variation of native and
oceanic cold ecologies.
The cold environment compound of hydrogen and carbon decomposers is also
found to be valuable for wastewater action. The use of thermophiles for biodegradation
of compound of hydrogen and carbon with little water solubility is of attention, as
solubility and thus bioavailability, are higher at raised temperatures.
The thermophiles, primarily bacilli, have a considerable probable for the
decomposition of surroundingl contaminants, containing all main classes. Native
thermophilic compound of hydrogen and carbon degraders are of distinct consequence
for the bioremediation of oil polluted desert soil.
The outcomes of present experiment exposed that the biodecomposition of
hydrocarbon were done by using different microbes with different environmental
condition as well as habitat (Margesin, et al., 2011).
The Industrial area was selected for the experimental study, In sewage water
collected from industrial area for laboratory experimental study, in this water
microorganism are isolated, separated and multiplicated which produces PHA.
The Pseudomonas oleovorans and Alcaligens eutrophus were isolated from
sewage water and there extraction was done by solvent chloroform method and the
extracted PHA was tested by different methods like Gas chromatography and Fourier
Transform Infrared FTI spectroscopy.
The gas chromatography occurs for specific polymer composition and Fourier
Transform Infrared spectroscopy for the structural and its functional group. (Kumar,
et al., 2011).
In this analysis decomposition of two type of plastics polyethylene and
polypropylene under in vitro situations is reported. The results shows that the
Pretreated plastic decompose more definitely as compared to the untreated plastic.
However, decomposition is more superficial with starch and cellulose mixed plastics.
The Cell surface hydrophobicity and adding of surfactants displayed an
significant part in creation of biofilm, which is essential for decomposition.
Decomposition indicates that to reduction in molecular weight, flexible strength and
thickness, creation of new efficient clusters such as carbonyl, hydroxyl (Arutchelvi, et
al., 2007).
The present research article study on the biodegradable plastics was précises
statistics on their use, decompability, profitable dependability and creation from
renewable resources.
Certain types of decomposable plastics are created on organic combination.
Others are produces of bacterial fermentations or are formed from organiically improved
natural yields. The growth of decomposable polymer is greatest observed in the setting
of diminishing of crude oil reserves (Flieger, et al., 2003).
A bacterium isolated from cotton growing soil was successfully exposed to
dcompose a pesticide endosulfan into endosulfan sulfate. The microbes decomposed
50 percent of the compound within three days of incubation. (Shivaramaiah, et al.,
2006).
This research article shows that the association between soil water land
capability and decoposition of polyester polyurethane and classify degrading
microorganisms in the biofilms on plastic buried in soil method.
The number of both fungi and bacteria were improved from biofilms on soil
suppressed, dumb bell shaped pieces of polyester PU after 44 days at 15 to 100% soil
water holding capasity. The flexible strength of the polyester PU was decreased by up
to 60% over 20 to 80% soil water holding capasity, but no decrease took place at 15 %,
90 % or 100% soil water holding capasity.
A PU agar permission assay specified that fungi, shows good results as compare
to bacteria and 10 to 30 percent of all the insulated fungi were capable to reduce
polyester in this test. 5.8S rDNA sequencing recognized 13 strains of fungi expressive
the three main colony morphology types accountable for PU decoposition.
The noticed strains of microbe were Nectria gliocladioides (five strains),
Penicillium ochrochloron (one strain) and Geomyces pannorum (seven strains).
Geomyces pannorum was the major bacterium in the biofilms including 22 to 100
percent of the feasible polyester PU decoposing fungi.
Polyester decoposition was optimal below a extensive series of soil water holding
capasity and the leading decomposing microbess were fungi. Importance and effect of
the experiment, by detecting the leading decomposing fungi in soil and studying the
optimal water holding capasity situations for decomposition of PU. It permits us to
superior recognize how polymer are destroyed in the surroundings such as in landfill
sites (Barratt, et al., 2003).
In the present experiment, soil sample were collected from polythene and plastic
put site waste in the area of Muthupet Mangrove. The physical and chemical factors of
the soil were calculated. From the collected sample microbes are separated, isolated for
the experimental study and seperated bacterial strains were recognized on the base of
their cultural morphological and biochemical study. The liquid culture methods are used
for the experiment.
The decomposition of polythene bag and plastic cup were examined for the
period of 35, 45 and 55 days respectively of incubation in liquid culture method. Pot
culture of Vigna radiata was implemented. The morphological factors likes incubating
capability, root length, shoot length and chlorophyll content were examined. Waste
controlling was the main method to defend the surroundings from toxic waste.
The polythene and plastic cups waste resources cause thoughtful ecological
difficulties, therefore the waste resources were deleted by consuming the microbes.
This system was cheaper and very active, so that it can be used extensively for the
handling of polythene and plastic cup (Kannahi, et al., 2013).
The present article study on the biodegradation of low density polyethylene,
samples were collected from municipal landfill are. Two types of fungal strains Mucor
circinilloides and Aspergillus flavus were isolated from the collected samples.
The degradation capabilities of the two fungal species were estimated by
performing colonization studies, SEM and Sturm test analysis. Colonization studies on
LDPE film was performed for a period of one month.
LDPE films colonized by fungus strain and observing structural changes in the
LDPE films. LDPE degradation by the fungal strains was further assessed by measuring
the CO2 evolved which was calculated gravimetrically and volumetrically by Sturm
test.The isolated fungi presented a capable degradation pattern as analysed by the here
mention three methods (Pramila, et al., 2011).
In this article eight species of microorganisms were identified as Alcaligens sp.,
bacillus sp., Acinetobacter sp., Pseudomotias sp., Arthrobacter sp. and Acetobacter sp.
These shows significant (p<0.05) degradation of a novel biodegradable acylated
cornstarch plastic in pure cultures.
The culture medium contained plastic dust as the only carbon basis at the time
of degradation after one to two weeks starch and glucose produced and degradation
was determined. This study indicates that the plastic degradation bacteria presence
in a variety of soil type, and also the capability of plastic degradation of the isolates in
soil types collected in Sri Lanka and Japan (Chrishanthi, et al., 2006).
In this review polyethylene plastic selected for the biodegradation study and to
separate exclusive microorganisms skillful of using artificial plastic. In thitics study photo
or thermo oxidation useful before contact to the biotic atmosphere, use of non-ionic
surfactants that will improve biofilm creation and Selection and isolation of beneficial
microbes.
The results shows that the decomposition of polymer waste with designated bacterial
strains developed a viable solution (Sivan, A. 2011).
In this review study done on Phthalates, they are created on enormous quantities
to create several types of polymer and have become extensive in surroundings. This
has been of an ecological anxiety because phthalates are hepatotoxic, teratogenic, and
cancer-causing by nature.
Various studies specified that phthalates could be decomposed by bacteria and
fungi under aerobic, anoxic, and anaerobic situations. This paper gives a review on the
decomposition of phthalates and contains the relationship between the organic
assembly of phthalates and their decomposibility, the decomposition of phthalates by
pure or mixed cultures, the decomposition of phthalates under different surroundings,
and the decomposition pathways of phthalates (Liang, et al., 2008).
In the current study the cultivated and kitchen wastes like as root vegetable,
shells, sugarcane waste, tree bark, used bacteriological media, newspaper, saw
powder, fruit shells, grasses, leaves, guar, used tea, spinach stems, timber damages,
fruit and vegetable wastes were used only and in mixtures as manure feed stocks.
From the above samples microorganisms separated, isolated and characterized
contain the species of fungi like Cladosporium, Monilia, Helminthosporium,
Coccidioides, Scedosporium, actinomycete viz., Nocardia Aspergillus, Trichoderma,
Mucor, Penicillium, Alternaria, and bacteria like Bacillus, Lactobacilli, Micrococcus,
Pseudomonas, Clostridium.
Therefore, these segregates associates of the genus Aspergillus were best
dominant (38%) then by Bacillus containing of 20% of the total bacterial separates. The
study supports the indication that composting can be beneficial to treat wide range of
carbon-based resources such as grass accessories, kitchen wastes and food treating
removes. In adding, the information concerning species configuration of the microbes of
dissimilar manures can help to enhance manure superiority criteria (Ashraf, et al.,
2007).
In this research study plastic bags are selected for the study, the properties of six
decomposable profitable plastic bags were studied.
The number of test were done are the effects of UV radiation, moisture exposure,
and weathering on mechanical properties were observed. The creep, tensile, and
thermal degradation behaviour of the bags were observed.
Normally the bags started to decopose thermally at about 400°C. ultraviolet
radioactivity, humidity, and enduring had minute result on thermal decomposition.
Oxobiodegradable and Flushdoggy became mainly brittle after faster elderly while the
properties of the traditional bags remained relatively similar.
The data indicated that biodegradable plastic bags could offer an alternative to
traditional plastic bags. Hence, because of biodegradable bags beneficial effects in
minimizing landfill contribution due to their capability to degrade at a quicker rate than
traditional plastic bags, it is expected that the use of such bags will rise. (Buckley, et
al., 2011).
The present review suggest that the polymer is a broad name given to dissimilar
plastics with large molecular weight, which can be decoposed by numerous methods.
Nevertheless, allowing for their richness in the atmosphere and their capability in
attacking polymers,decomposition of polymers by microbes and enzymes appears to be
the best operative process.
When polymers are utilised as substrates for biodegradation microbes,
assessment of their decomposibility should not only be based on their chemical
structure, but also on their physical possessions like melting point, glass transition
temperature, crystallinity, storage modulus etc.
The current research paper examines the opportunity of polymer decomposition
by microorganisms seperated from of forest soil samples. Burial method were used for
this experiment, invitro decomposition was studied by litter bag experiment by taking 1 g
of each plastic and suppressed under forest soil at a distance of 15 cm from the above
surface throughout the month of september to february, 2010.
An in vitro experiment was ongoing after gathering the plastic samples from the
litter bag experiment and the microorganisms were separated from the surface of the
polymers. Then the seperated microorganisms injected in the nutrient agar.
The serial dilution plating technique was made to isolate the bacteria and fungi
Gram’s staining and Biochemical tests have also been alone. Identification of the
bacteria was done by using Bergy’s manual of determinative bacteriology. For bacterial
degradation of 24 hrs culture of Micrococuus luteus and Masoniella sp were inoculated
into the flask containing 250ml of sterile nutrient broth, 1.000 gm of plastic cup were
transferred into separate flasks control condition was maintained without any bacterial
culture. The Inoculated flask was placed in shaking incubator for 35, 45 and 55 days
respectively .
The results deduced show that different types of polymers decomposition done
under suppressed method during period 45 days. In the present study, plastics are
highly resistant to degradation of plastics by using microorganisms is a great challenge.
Hence, an attempt has been made to determine the plastics degrading capability of
Micrococcus luteus and Masoniella sp.( Sivasankari, et al., 2014).
In the present review study done on hazards of plastic is a wide name specified
to the various types of organic polymers having large molecular weight and is usually
resulting from dissimilar petrochemicals. Plastics are generally not decomposable or
very few are decomposable but degradation is at actual relaxed speed. Day by day, the
overall response of these polymers is severely rising; though, considering their richness
and potentiality in producing dissimilar ecological threats, there is a excessive anxiety in
the probable approaches of biodegradation of plastics waste.
In recent times, there have been some arguments at the world wide around
regarding the possible decomposition events of these artificial plastics and bacterial
decomposition has arose as one of the possible substitute ways of decomposition of
polymers. Otherwise, some researchers have also reported many opposing special
effects of these polymers on human health, and thus, there is an urgent necessity of a
possible broadcast of some possible microorganisms to decompose these artificial
polymers.
In the present review, an effort to gather all evidence concerning the chemical
nature along with some possible microorganisms and their enzymatic nature for
purpose of decomposition of polymers along with some key elements that affect their
decomposition.
The objectives of this review literature are to study the nature and classification
of plastic and its effect on the ecosystem including the human health hazards and to
categorize the potential microbes and their mechanisms of biodegradation of different
plastic products. This work will provide a ready reference for further scientific research
exploration of these potential microbes (Ghosh, et al., 2013).
This review microbes species like Pseudomonas flourescens and Bacillus
subtilis are used for the study. These microbes’ species capable of creating Lipase and
demeaning poly Butylene Succinate was insulated and partitioned using PBS
improvement medium and Tributyrin medium.
Supplementary the enzyme Lipase was insulated and disinfected using
ammonium sulphate precipitation, DEAE cellulose and sephadex column
chromatography. The action of the enzyme was initiate to be growing at each step of
sanitization.
The optimal pH and temperature of the enzyme was noted as seven and 37°C
respectively. A weight loss recoded of 30 percent, 35 percent and 50 percent was
seen in case of PBS films when preserved with lipase (Pseudomonas flourescens and
Bacillus subtilis, commercial) which imitates their specificity towards their substrate.
The level of decomposition of PBS was advance established by SEM
examination where dissimilar sized outbreaks were seen in PBS films when injected
with Lipase from diverse bases signifying that Lipase has the specificity towards the
substrate PBS in decomposition.
Thus, this study concluded that the enzyme Lipase was proved to be the PBS
degrader was highly active at pH 7 and at temperature 37°C and thus the same
environmental condition was also very effective in degrading Poly Butylene Succinate
(Asheeba, et al., 2011).
This review found that decomposition of polycyclic aromatic compound of
hydrogen and carbon from free living microorganisms in soil or water methods were
practical to survey pattern biodiversities.
The predominant free alive species, Brevundimonas (Pseudomonas) diminuta,
Caulobacter species., Mycoplana bullata, Acidovorax species. and Pseudomonas
aeruginosa, can be noticed by fluorescence in situ hybridization (FISH). (Chang, et al.).
This review found that the study of the creation of poly-3-hydroxybutyrate (PHB)
under partial nitrogen situations by Bacillus sphaericus NII 0838 using crude glycerol
from biodiesel industry as only carbon basis.
This current investigation demonstration that there is a extensive opportunity for
consuming the crude glycerol byproduct from biodiesel industry for biologically
approachable bio-plastics creation. The strain Bacillus sphaericus NII 0838 created 31
percent PHB in N-limited medium using crude glycerol as only carbon basis. Further
these microbial isolates are being separated and tested to find out their efficacies to
degrade plastics (Gupta, et al., 2010).
In the current analysis study of the total composting procedure of vegetable, fruit
and garden wastage , based on relationships between microbial counts, functional
groups, species variety and abiotic features (Ryckeboer, et al., 2003).
In this review study of thirteen bacterial and actinomycetes strains capable of
degrading BOPP have been isolated from compost and air. Most of them are
actinomycetes and some are bacteria. The bacterial isolates are gram positive and
belong to genus Bacilli. Actinomycetes are showing Gram positive, rod shaped
character.
Weight loss of polymer kept in synthetic media for two months at 370C varies
from 0.66% to 4.38% with average value of 2.01%. The same value in compost is 8.2
%. Weight loss in polymer confirms the degradation of polymer. By growth kinetic study
in synthetic media, it is concluded that isolated strains are solely dependent on BOPP
films for its carbon source. FTIR spectra also confirm the biodegradation of polymer as
some chemical change are seen in surface of polymer (Jain, 2011).
In this study, the biodegradation of polythene bag was analyzed 1 month of
incubation in liquid culture method. Bacterial amount showed that 0.0278×109 per gram
for total heterotrophic bacteria. The bacterial species start associated with the
decomposing resources was identified as two Gram positive and five Gram negative
bacteria. The identified microorganisms are as Bacillus subtilis, Bacillus amylolyticus,
Arthobacter defluvii.
The efficiency of microorganisms in the decomposition of polymers were
examined in liquid (shaker) culture method, among the bacteria Bacillus amylolyticus
degrades plastic more in 1 month (30% weight loss/month) period compared to others
and leser degradation rate was seen in case of Bacillus subtilis(20% weight
loss/month). This work clearly reveals that Bacillus amylolyticus possess higher
prospective to decompose polymers when related with other bacteria. (Thakur)
Unlike polypropylene, further research articles are published on studies linking
to decomposition of polyethylene. Fungi that include A. niger, Penicillium funiculosum,
A. vesicolor, Fusarium redolens and soil microbes (mixed culture as well as
Rhodococcus rhodochorus, Cladosporium cladosporoides) have been described to
decompose neat PE (Albertson et al., 1995; Shah et al., 2008; Ramis et al., 2004).
DSC or FTIR and other automated and physical methods such as weight loss,
variations in flexible strength have been the frequently utilized logical techniques
to display the nature of decomposition. Thermal, UV, photo and corona treated PE
has been initiate to decompose faster as relate to the untreated plastic.
The decomposition of starch combined and changed polyethylene with protein
hydrolysate has also been calculated El-Shafei et al. (1998). At least two types of
enzymes are vigorously convoluted in biological decomposition of polymer, extracellular
and intracellular depolymerases (Doi, 1990; Gu et al., 2000).
Throughout the process of decomposition, exo enzymes from microbes
breakdown difficult plastics yielding short chains or lesser particles.
Plastic like cellulose, chitin, pullunan, and PHAs are all naturally manufactured
and can be totally and quickly decomposed by microbes in a extensive variety of
natural surroundings (Chahal etal., 1992; Frazer, 1994; Sonne-Hansen et al., 1993).