Microbe Metal

8/8/2019 Microbe Metal

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THE ROLE OF MICROBES IN

METAL TRANSFORMATION

Irfan D. Prijambada


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METAL TRANSFORMATION

Metal lower valence+ Metal higher valence+

OXIDATION

REDUCTION


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CHARACTERS OF

LOWER VALENCY METAL ION Soluble and stable

Accumulated under reductive condition Readily oxidized into its higher valence

metal ion


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CHARACTERS OF

HIGHER VALENCY METAL ION Soluble at lower pH

Insoluble at neutral and alkalinecondition


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PROBLEMS REGARDING

IONIC METAL Unavailability of metal ion under

oxidative condition at neutral to alkalinepH (higher valence of metal ioninsoluble at neutral to alkaline pH)

Toxicity of metal ion under oxidative

condition at acidic pH (higher valence ofmetal ion soluble at acidic pH)


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THE ROLE OF MICROBES IN SOLVINGTHE UNAVAILABILITY OF METAL ION UNDEROXIDATIVE CONDITION AT NEUTRAL TO

ALKALINE PH

Local acidulation by producing acid(lowering local pH)

Local reduction of higher valence metal(lower valence metal soluble at any pH)

Chelation by producing chelating agent(transporting metal ion into plantwithout changing their valence)


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LOCAL ACIDULATION BY

PRODUCING ACID Done by any kind of microbes

As intermediate products of microbesmetabolism


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LOCAL REDUCTION OF

HIGHER VALENCE METAL Done by many kind of microbes such as

Bacillus, Pseudomonas, Proteus,Alcaligenes, Clostridia, andEnterobacteria

Link to nitrate reduction system


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CHELATION OF HIGHER VALENCE METAL

BY PRODUCING CHELATING AGENT

Chelating agents entrapped the insolublehigher valence metals

Enterobacteria produce Enterobactin andEnterochelin (derivatives of Phenol-Catechol)

Streptomyces and other bacteria produceFerrioxamine (derivatives of Hydroxamic

acids) Chelating agents have multiple hydroxyl or

carbonyl groups


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THE ROLE OF MICROBES IN SOLVINGTHE TOXICITY OF METAL ION UNDER

OXIDATIVE CONDITION AT ACIDIC pH

Producing carboxylic acids such as citric

acid, malic acid, oxalacetic acid, succinicacid, lactic acid, and acetic acid

Carboxylic acids have a chelatingcapability, increasing metal content ofplant (which means increasing metalabsorption by the plant) withoutharming them


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CHELATING CAPABILITY OF

CARBOXYLIC ACIDS

Can be used to increase plant absorption

of metal (for bio and phytoremediatingmetal polluted land)


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ACCUMULATION OF LEAD IN

THE ROOT OF DICOTYLPlants Lead Accumulated in

the Root (mg/g)

Brassica juncea 136

B. oleracea 134

Helianthus annuus 140

Nicotiana tabacum 132

Spinacea oleracea 95


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ACCUMULATION OF LEAD IN

THE ROOT OF MONOCOTYLPlants Lead Accumulated in

the Root (mg/g)

Secale cereale 136

Sorghum bicolor 134

Zea mays 140


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ACCUMULATION OF LEAD IN THE ROOT

OF WINTER GRASSES AND SHRUBS

Plants Lead Accumulated in theRoot (mg/g)

Agrostis tenuis 169

A. palustris 146

Eragrostis curvula 142

Poa pratensis 165

P. trivialis 100

Lolium perenne 134

Festuca ovina 125

F. Rubra 86

F. Arundinacea 85

Dactilys glomerata 60


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ACCUMULATION OF LEAD IN THE ROOT

OF SUMMER GRASSES AND SHRUBS

Plants Lead Accumulated inthe Root (mg/g)

Eremochloa ophiuroides 124

Buchloe dactyloides 118

Panicum virgatum 116

P. Amarum 109

Cynodon dactylon 90

Zoysia japonica 56


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OTHER ROLE OF MICROBES IN

REDUCING METAL POLLUTION

Absorbing metal ion by utilizing functional groupsexist in the cell wall

INTERACTION MACROMOLECULES FUNCTIONAL GROUPS

IONIC Phosphomannan Phosphates

POLAR Polysaccharides,Chitin, Chitosan

Hydroxyls, Aminos,Carboxyls

COMBINATION Proteins Aminos, Hydroxyls,Amides, Carboxyls, Thiols

MINERAL Anion Polymers Phosphates, Carboxylic

acids


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STRONG-WEAK ANION-CATHION

INTERACTION (According to Lewis)

Strong Cathion Medium Cathion Weak Cathion

H+

, Na+

, K+

, Be2+

,Mg2+, Ca2+, Mn2+,Al3+, Fe3+, Co3+,

As3+, Cr3+

Pb2+

, Zn2+

, Al2+

,Fe2+, Co2+, Ni2+,Cu2+

Cu+

, Ag+

, Au+

, Ti+

,Hg2+, Cd+

Strong Anion Medium Anion Weak Anion

OH-, F-, Cl-, PO43-,

SO42-, CO3

2-, O2-,

CO2-

Br-, NO2-, SO3

2- SH-, S2-, RS-, CN-,SCN-, CO, R2S, RSH


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METAL ABSORPTION BY

MICROBES Uranium is absorbed by the cells of

Pseudomonas aeruginosa,

Saccharomyces cerevisiae, Rhizopusarrhizus, and Aspergillus niger

Thorium is absorbed by the cells of R.arrhizus, and A. niger

Mercury is absorbed by the cells of S.cerevisiae


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METAL ABSORBING

MICROBES Pseudomonas aeruginosa,

Saccharomyces cerevisiae, Rhizopusarrhizus, and Aspergillus niger

ALGAE: Chlorella pyrenoidosa, C.vulgaris, Chaetoceros calcitrans,

Stichococcus bacillaris, Chlamydomonasreinharti, Scenedesmus quadricauda,

Ascopenyellum sp., and Sargassum sp.

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Microbe Metal