The use of microalgae in biotechnological applications

The use of microalgae in

biotechnological applications:

Case Studies

Maria Georgakopoulou

SCHOOL OF ECONOMICS, BUSINESS ADMINISTRATION &

LEGAL STUDIES

A thesis submitted for the degree of

Master of Science (MSc) in Bioeconomy Law, Regulation and

Management

November 2018

Thessaloniki – Greece

Maria Georgakopoulou, “The use of microalgae in

biotechnological applications: Case studies.”

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Student Name: Maria Georgakopoulou

SID: 4402170001

Supervisor: Dr. Savvas Genitsaris

I hereby declare that the work submitted is mine and that where I have made use of

another’s work, I have attributed the source(s) according to the Regulations set in the

Student’s Handbook.

November 2018

Thessaloniki - Greece



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Acknowledgements

The present dissertation would not be possible to accomplish without the valuable

guidance and constructive suggestions, during the planning and development of the

research work, of my research supervisor, Dr. Savvas Genitsaris, to whom I am grateful

for his contribution and mentoring through the Master's program and on all aspects of

my educational course at the International Hellenic University.

My grateful thanks are owned to Mr. Vítor Verdelho Vieira, President of the

European Algae Biomass Association for his willingness to give valuable information

and induced me in the microalgae applications, strengths and limitations, through a very

educative and thorough interview.

Finally, I would like to express my gratitude, love, and respect to my family and my

husband for putting up with me and supporting my ventures, with their loving care and

encouragement.

Maria Georgakopoulou

30 November 2018



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Abstract

This dissertation was written as part of the MSc in Bioeconomy Law, Regulation and

Management at the International Hellenic University.

The first part of the present dissertation is about the uses and applications of

microalgae and cyanobacteria in the commercial and industrial sector. The great

potential of the microorganisms is highlighted in the various fields of human food,

animal feed, health, cosmetics, and pharmaceuticals, as microalgae and cyanobacteria

are a rich natural source of bioactive compounds, with antioxidant, antiviral,

antibacterial and anti‐inflammatory biological activities. At the energy sector, they have

the ability to produce biofuels such as biodiesel, biogas, biomethane and bioethanol, as

a renewable source and as an alternative to the exhaustible fossil fuels. Finally,

microalgae and cyanobacteria have certain environmental applications, such as the

ability to produce bioplastics, and contribute to the treatment of wastewater and to the

bio-mitigation of CO2.

The second part includes a SWOT analysis of the microalgae production and market

sector, continuing with the sustainability evaluation of the food and energy sector, as

those two are the ones with the greater importance and focus of research, as well as

public and private funding initiatives. In conclusion, the dissertation attempts to link the

microalgae potential and applications to the European principles of Bioeconomy and

circular economy, as they are expressed through the relevant action plans recommended

by the European Commission. In addition, a sustainable business model is proposed,

consisting of three stakeholders, at the phases of cultivation, bio-based product

development and waste management and recycling, in accordance to these strategies,

emphasizing the high degree of applicability and integration to the European plan.

Microalgae and cyanobacteria, besides the great potential they reveal, are yet far from

being large-scale industrially exploited due to the high costs of production. More

efficient production systems need to be designed, with the contribution of the

technological advancement in order to fully utilize the abilities of microalgae.

Keywords: microalgae, cyanobacteria, commercial applications, business model,

sustainability



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Contents

CONTENTS ................................................................................................................. IV

LIST OF FIGURES ....................................................................................................... V

LIST OF TABLES ....................................................................................................... VI

INTRODUCTION .......................................................................................................... 1

WHAT ARE MICROALGAE? ........................................................................................... 1

AIM OF THE STUDY ....................................................................................................... 5

METHODOLOGY ......................................................................................................... 6

RESULTS ...................................................................................................................... 6

MICROALGAE APPLICATIONS ............................................................................... 9

FOOD AND FEED ........................................................................................................... 9

HEALTH ..................................................................................................................... 11

BIOFUELS ................................................................................................................... 16

BIO-MITIGATION OF CO2 EMISSIONS USING MICROALGAE .......................................... 22

COSMETICS ................................................................................................................ 25

SWOT ANALYSIS ....................................................................................................... 30

SUSTAINABILITY EVALUATION OF MICROALGAE MARKET SECTORS33

SUSTAINABILITY AND FINANCIAL EVALUATION OF THE FOOD SECTOR ..................... 34

SUSTAINABILITY EVALUATION OF THE BIOFUELS SECTOR ........................................ 38

THE CONTRIBUTION OF MICROALGAE IN BIOECONOMY AND CIRCULAR ECONOMY ... 40

CONCLUSIONS ........................................................................................................... 47

BIBLIOGRAPHY ......................................................................................................... 50



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List of Figures

Figure 1 Main components of typical microalgae. Modified from: Schmid-Straiger,

2009. 3

Figure 2 Representation of some of the most commercial microalgae species: 4

Figure 3 Graphical representation of general research on microalgae from 1960 to 2018.

6

Figure 4 The progression of biotechnological research on microalgae and cyanobacteria

over the last decade. 7

Figure 5 World map with chromatic depiction of countries and their contribution in

biotechnological research on microalgae. 8

Figure 6 Current uses of microalgae, from direct use to the formation of by-products. 9

Figure 7 Microalgal biomass conversion processes and forms of energy obtained. 17

Figure 8 Proposed sustainable microalgae business model 42



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List of Tables

Table 1. General composition of human food sources compared to microalgae and

cyanobacteria (% of dry matter) 10

Table 2. Examples of microalgal and cyanobacterial PUFAs 12

Table 3. Oil content of various microalgae species: 18

Table 4. Comparison of microalgae with other biodiesel feedstock: 18

Table 5. Potential microalgae products, use and selling price 20

Table 6. Microalgae and cyanobacterial applications in cosmetics 25

Table 7. List of algal biotechnological companies. 27

Table 8. SWOT analysis on microalgae and cyanobacteria. 30

Table 9. Market information on microalgae and cyanobacterial -derived products 35

Table 10. Food commodities from microalgae: overview of key features, which need to

be considered to enable successful sustainable, cost effective and safe product

applications. 36

Table 11. European Union action plan for Bioeconomy and the contribution of

microalgae 43

Table 12. European Union action plan for Circular economy and the contribution of

microalgae 44

Maria Georgakopoulou, “The use of microalgae

in biotechnological applications: Case studies.”

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Introduction

The global climate change has caused dramatic effects in the availability of resources,

mainly affecting the food and energy sectors. A bio-based economy, as the one proposed by

the European Union, requires agricultural crops to be used not only for food and feed but

also for chemicals, materials and even biofuels. The scarcity of the available fossil

resources increases the demand for alternative, bio-based products, with multiple uses.

Therefore, the debate on whether the production capacity for food and non-food products

will be sufficient, remains (Draaisma et al., 2013). The parallel rise of global population,

estimated to reach nine billion in 2050, has forced the investigation of alternative sources,

in order to find novel and sustainable solutions in the major problems we will be called to

answer in the near future.

In order to be able to face effectively these challenges, new methods of production need

to be examined, with the help of marine biotechnology (Submariner project, 2011).

Microalgae are considered one of the most favorable and potent feedstocks for a

sustainable supply of products aimed to the food and energy market (Milledge, 2011;

Wijffels and Barbosa, 2010; Williams and Laurens, 2010). The promising alternative of

microalgae and cyanobacteria, which have the ability to contribute to multiple scientific

fields, showing a positive outlook for the future, could take advantage of the state-of–the-

art scientific and biotechnological developments, and act as a sustainable resource with

significant potential (Fortes Siqueira et al., 2018; Stephens et al., 2013).

What are microalgae?

Microalgae are microscopic aquatic photosynthetic microorganisms, they are

autotrophs and they have the ability to transform sunlight, carbon dioxide and nutrients into

biomass (Sigamani et al, 2016). The field of microalgae research includes not only the

eukaryotic microalgae but also the prokaryotic oxygenic Cyanobacteria.



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The reason is the similarity they show, on the products developed and their applications in

various fields, as well as their similarity in the basic and essential parts of their production

(Garrido-Cardenas et al, 2018).

Microalgae exist in every ecosystem on earth, aquatic and terrestrial, with a variety of

more than 50.000 species, but with approximately 30.000 species being the object of

studying and scientific analysis (Richmond, 2004), and only about 100 species being used

for commercial applications (Su et al., 2017). The classification of microalgae is conducted

by pigmentation, life cycle and cellular structure, nonetheless, newer species are detected

by the novel next-generation sequencing technologies (Ebenezer et al., 2012; Brennan &

Owende, 2010).

The metabolic flexibility of microalgae, with their unicellular formation, permits them to

adapt in a variety of environments, even with the presence of unsuitable conditions, due to

their physiology, which relies on the accumulation of high added-value compounds

(Guedes et al., 2011), as depicted in Fig 1. The chemical composition varies on a large

scale, as differentiation occurs even among strains, mainly due to the variation in

environmental factors, such as the temperature, sunlight, pH range, CO2, nitrogen,

phosphorus, sulfur and other nutrients' supply (Becker, 2004). The composition therefore

can be manipulated, modifying the algal constituents and varying the culture conditions,

alternating as well, the commodity produced and its characteristics (Forján et al., 2015).

The most common systems used for the cultivation of microalgae, are mainly the open

systems (i.e. circular and raceway ponds), in natural and artificial waters, and closed

systems, which are developed to overcome the limitations of the first (i.e. tubular, vertical

columns and flat-panel photobioreactors) (Rodolfi et al., 2009; Carvalho et al., 2006). After

cultivation, the biomass must be harvested, in a process that separates the solid matter

(biomass) from the liquid (culture medium). Different methods are used for harvesting,

even though the process has difficulties due to the small size of the cells of some

microalgal species (2 to 40 μm), as well as due to economic reasons (Lee et al., 2014).



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It is the unique adaptability of microalgae and cyanobacteria, which allows them to

provide energy for growth and preservation, what characterizes them and makes them

suitable as a sustainable renewable source in a circular economy strategic environment

(Herador, 2016). More specifically, microalgae and cyanobacteria have the ability to

develop and withstand harsh environmental conditions, such as heat, cold, anaerobiosis,

salinity, photo‐oxidation, osmotic pressure and exposure to ultra‐violet radiation (Christaki

et al., 2012). They are also described by their short life cycles, fast growth rates, high

productivity, limited seasonal variation and cheap cultivation with abundant raw materials

(Christaki et al., 2012). They do not need arable land to grow or fresh water and thus, have

a clear advantage compared to the conventional plants.

One of their most important attributes is the plasticity they show which gives them the

ability to use the same cultivation process for multiple applications (Wang et al., 2015),

such as food and energy, cosmetics, pharmaceuticals and wastewater treatment.

Figure 1 Main components of typical microalgae. Modified from: Schmid-Straiger, 2009.



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Their great potential in biotechnological exploitation, is, therefore, supported in the

diversity of important applications they have the ability to develop, in many technological

lines of production (Fortes Siqueira et al., 2018). Fig. 2 shows a representation of the most

commercial microalgae species used today for commercial and industrial purposes.

Figure 2 Representation of some of the most commercial microalgae species:

a. Chlorella vulgaris1 b. Arthrospira platensis2 c. Botryococcus braunii3 d. Dunaliella salina4

e. Haematococcus pluvialis5 f. Scenedesmus quadricauda6

1 a. https://botany.natur.cuni.cz/algo/CAUP/H1917_Chlorella_vulgaris.htm 2 b. https://microbewiki.kenyon.edu/index.php/Arthrospira_platensis 3c.https://www.interempresas.net/Energia/Articulos/42002-La-biomasa-algal-una-potente-fuente-

de-energia.html 4 d. https://www.algotherm.com/en/seaweed/dunaliella-salina-en/ 5 e. https://www.flickr.com/photos/wunderkanone/5107180765 6 f. https://www.researchgate.net/figure/Scenedesmus-diagram-and-image_fig1_317328196



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Aim of the study

The objective of the present study is to examine the most recent advancements in the

research regarding the uses of microalgae and cyanobacteria, on a global scale, in order to

emphasize the recent breakthroughs on the topic.

On a more specific basis, the first part of the study aims to summarize the commercial

applications of microalgae and cyanobacteria in the commercial and industrial sector,

highlighting the potential developments, the advantages and benefits reported in the

international literature and the various applications in the fields of human food, animal

feed, health, biofuels, cosmetics, and pharmaceuticals, as well as certain environmental

applications, such as the ability to contribute to the treatment of wastewater and to the bio-

mitigation of CO2.

On the second part of the study, a connection will be attempted of the microalgae and

cyanobacteria uses to the principles of Bioeconomy, circular economy and sustainability in

commercial application of the microalgal products, on a European Union level.

Sustainability evaluations of the food and energy sector are attempted, as those two sectors

are the ones with the greater importance and focus of research, as well as public and private

funding initiatives. A sustainable business model is proposed with practical application to

the aforementioned concepts, emphasizing the high degree of applicability and integration

to the European plan. Attention will also be drawn to the Strengths, Opportunities,

Weaknesses and Threats of the industrial and commercial sector, performing a relevant

SWOT analysis of the microalgae-based products and applications used and developed in

the European and global market.



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Methodology

Exhaustive searches of the Elsevier Scopus and ScienceDirect databases were performed,

using the keywords [microalgae, algae, cyanobacteria, phytoplankton, biotechnology,

biotechnological applications, bioprocesses, biofuels, microalgae food, microalgae

cosmetics, sustainability (alone or in combination)] in the sections of "Article title,

Abstract, Keywords" in Scopus and "Keywords" of ScienceDirect, without applying any

date or document type limitations to the results. The search produced thousands of

documents from 1960 until 2018. The results were grouped and reviewed, eliminating the

ones which did not fit to the profile of the study.

Results

The research on the field of microalgae seems to be increasing exponentially over the last

decade, as observed in Fig. 3, along with the development of technologically advanced

facilities and commercialization of products based on microalgae:

Figure 3 Graphical representation of general research on microalgae from 1960 to 2018.



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More specifically, the research on microalgae and cyanobacteria, concerning

biotechnological applications and the contribution of the two organisms in biotechnology in

general, for the last decade, has the following progression, as depicted graphically in Fig. 4:

Figure 4 The progression of biotechnological research on microalgae and cyanobacteria over the

last decade.



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A representation of the worldwide scientific publications on biotechnology research on

microalgae and cyanobacteria is depicted on Fig. 5. USA, China, Spain, France, India,

Australia, Germany, Japan, United Kingdom, South Korea and Italy, are the leader

countries in microalgae and cyanobacteria biotechnological research and publication.

Figure 5 World map with chromatic depiction of countries and their contribution in

biotechnological research on microalgae.



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Microalgae applications

Microalgae biomass, depending on the species and the extracted compounds, has a wide

application in various fields, such as human and animal nutrition, pharmaceuticals,

cosmetic products and the production of renewable energy sources. Fig. 6 represents

graphically the variety of the uses of the microalgae biomass, from direct use as food and

feed to the bioproducts and biofuels, derived from microalgae cultures, with parallel

environmental ramifications.

Food and feed

Microalgae and cyanobacteria are known to be cultivated for food purposes (Gantar and

Svircev 2008; Chacón-Lee and González-Mariño 2010). The Food and Agriculture

Organization of the United Nations (FAO), has highlighted the tendency towards the

increase of demand for algal products on a global scale, as food supplements or as food

additives (FAO, 2016). Other industrial, legal/governmental and even nutritional concerns

Figure 6 Current uses of microalgae, from direct use to the formation of by-products.



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have led algal research to develop novel food products and dietary supplements

(Borowitzka 2013).

Due to their biochemical composition, microalgae can affect positively the human and

animal well-being. Microalgae and cyanobacterial species are known to have high levels of

protein with vital amino acids and lipids with fatty acids, found also in the conventional

food, in bigger quantities and better quality (Ward and Singh, 2005; Guerrero et al., 2004).

Table 1 shows a comparison between conventional food and microalgae, in terms of protein

levels, carbohydrates and lipids.

Table 1. General composition of human food sources compared to microalgae and

cyanobacteria (% of dry matter)

Conventional foods Protein Carbohydrates Lipids

Bakers yeast 39 38 1

Egg 47 4 41

Meat 43 1 34

Milk 26 38 28

Rice 8 77 2

Soya 37 30 20

Species Protein Carbohydrates Lipids

Anabaena cylindrica

Aphanizomenon flos‐aquae

43 to 56 25 to 30 4 to 7

62 23 3

Arthrospira maxima 60 to 71 13 to 16 6 to 7

Chlamydomonas rheinhardtii

Chlorella pyreinodosa

48 17 21

57 26 2

Chlorella vulgaris 51 to 58 12 to 17 14 to 22

Chlorella vulgaris 47.82 8.08 13.32

Dunaliella salina

Euglena gracilis

57 32 6

39 to 61 14 to 18 14 to 20

Haematococcus pluvialis 48 27 15

Isochrisis galbana 26.99 16.98 17.16

Nannocloropsis spp. 28.8 35.9 18.36

Porphyridium cruentum 28 to 39 40 to 57 9 to 14

Porphyridium cruentum 34.1 32.1 6.53

Scenedesmus obliquus 50 to 56 10 to 17 12 to 14

Spirogyra sp. 6 to 20 33 to 64 11 to 21

Spirulina platensis 63 15 11

Spirulina platensis 61.32 to 64.43 15.09 to 15.81 7.09 to 8.03

Synechococcus sp. 46 to 63 8 to 14 4 to 9

Modified from: Chacón-Lee and González-Mariño 2010



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Microalgae and cyanobacteria are an important source of almost the majority of the

vitamins needed to the human organism, highlighting further the value of the microalgal

biomass for nutritional purposes. The considerable vitamin content includes vitamins A, B1,

B2, B6, B12, C, E, K, nicotinic acid, biotin, folic acid and pantothenic acid (Becker, 2004).

The concentration of the vitamins though, is affected directly from environmental factors,

as well as the methods of drying and harvesting treatment.

Microalgae and cyanobacteria based products are commercially available in the form of

capsules, tablets or as additives to commodities such as beverages, pasta, candy and gums,

for nutritional purposes or as coloring agents (Liang et al., 2004). The cyanobacterium

Arthrospira platensis (also known as Spirulina) and microalgae species, such as

commercial species of the genus Chlorella are already available in the market, as dietary

supplements, without any processing, other than drying.

The aforementioned are a good source of proteins and amino acids which human cannot

compose and, therefore, must acquire from food (Wells et al., 2017).

Along with Dunaliella, Haematococcus and Aphanizomenon, their production is

developed at large scale for use in the human and animal nutrition (Forján et al., 2015). In

fact, an estimated 30% of the annual production of microalgae, is directed to animals and

aquaculture, in order to supply vitamins, vital fatty acids and minerals and reinforce the

immune and reproductive system, control weight and improve appearance (Forján et al.,

2015).

Health

Microalgae and cyanobacteria are an excellent source of bio active compounds (Becker,

2004). They have the ability to produce polysaccharides, based on monomeric sugars, such

as glucose, important for medical purposes, synthesize cellulose, hemicelluloses, β-carotene

and other carotenoids (0.1% to 0.2% of dry weight - 14% of dry weight for β-carotene of

Dunaliella salina), commercially applicable natural colorings, such as astaxanthin (mostly

derived from Haematoccocus pluvialis), which is used in the health industry to treat

Alzheimer's and Parkinson's disease, to treat the metabolic syndrome and improve sleep,



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chlorophyll (0.5% to 1% of dry weight), and phycobiliproteins (Spolaore et al., 2005). The

aforementioned substances are essential to the treatment of tumors, neuronal disorders and

sight disorders. The elevated amounts of carbohydrates, make them an excellent energy

source (Guil-Guerrero et al., 2004). The lipids produced in the microalgae cells, are in large

amounts and are characterized by their variety depending on the species (Duong et al.,

2015). Certain microalgal products help control hyperglycemia and hyperlipidemia,

contributing medicinally to diabetic and obesity disorders.

The microalgal fatty acids are interesting not only for their nutritional but also for their

therapeutic applications. Polyunsaturated fatty acids (PUFAs), such as Omega-3 and

Omega-6, derived from microalgae, are considered important for the treatment of asthma,

arthritis and cardiac diseases (Adarme-Vega et al., 2012). Eicosapentaenoic acid (EPA) and

docosahexaenoic acid (DHA), linoleic acid, gamma-linolenic acid and arachidonic acid

have also commercial interest, and are known to balance cholesterol, prevent

cardiovascular disorders and have anti-ageing effect (Bannenberg et al, 2017), as well as

treat inflammatory diseases. Examples of microalgae species that synthesize fatty acids are

Arthrospira platensis (Cyanobacterium), to which sitosterol, stigmasterol, and γ-linolenic

acid are detected, Odontella, Porphyridium cruentum, I. galbana, and Pavlova lutheri, the

last known for its large quantity production (Santhosh et al., 2016). Table 2 lists examples

of microalgal and cyanobacterial PUFAs and their potential applications:

Table 2. Examples of microalgal and cyanobacterial PUFAs

PUFA Structure Potential

Application

Microorganism

Producer

Ref.

γ-Linolenic acid

(GLA)

18:3 ω6, 9, 12 Infant formulas for

full-term infants

Arthrospira Robles Medina

et al., 1998

Nutritional

supplements

Arachidonic acid

(AA)

20:4 ω6, 9, 12 ,15 Infant formulas for

full-term/preterm

infants

Porphyridium Molina Grima

et al., 2003

Nutritional

supplements



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PUFA Structure Potential

Application

Microorganism

Producer

Ref.

Docosahexaenoic

acid (DHA)

22:6 ω3, 6, 9, 12,

15, 18

Infant formulas for

full-term/preterm

infants

Crypthecodinium,

Schizochytrium

Jiang et al.,

1999

Nutritional

supplements

Aquaculture

Eicosapentaenoic

acid (EPA)

20:5 ω3, 6, 9, 12,

15

Nutritional

supplements

Nannochloropsis,

Phaeodactylum

Nitzschia

Belarbi et al.,

2000

Aquaculture

Modified from: Spolaore et al., 2006

Other microalgal species contribute to the prevention of oxidative stress, with substances

that act as antioxidants, with high medicinal benefit, protecting the human body from the

effects of free radicals (Khan et al., 2018). Due to the fact that microalgae have the ability

to produce bioactive natural antioxidant compounds, they have become one of the most

profitable sources in the sector of natural medicinal plants (Cornish and Garbary 2010).

Intensive marketing efforts as well as renowned health food press have led the public

attention towards the benefits of antioxidants, emphasizing the importance of using natural

sources (partially obtained from microalgae) other than synthetic compounds. For instance,

Phycoerythrobilin (from Porphyra sp.) reports significant antioxidant activities (Yabuta et

al., 2010), while chlorophyll and its metabolites as well as most of the pigments produced

(fucoxanthin and auroxanthin from Undaria pinnatifida) are regarded to have better

antioxidant properties than β-Carotene (Sangeetha et al., 2009).

Fucoxanthin, fucoxanthinol and siphonaxanthin, have also proved to suspend

angiogenesis, which, despite the fact that it is a natural process, it can become pathological

in the cases of cancer, ischemic stroke, diabetic retinopathy and atherosclerosis (Sugawara

et al., 2006; Armstrong et al., 2011). Furthermore, fucoxanthin has proved to protect DNA

from photooxidation (Heo et al., 2009). Cyanobacteria are thought to be considerable

sources of active substances which can help treat cancer.

Extracts of Synechocystis sp. and Synechococcus sp., Lyngbya sp., Anabaena sp., species

of Nostoc, the Oscillatoria boryana extract and Microcystis sp. have all proved to produce

substances, which induce apoptosis. Also, they produce bioactive metabolites and a variety



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of toxic compounds with important anti-cancer activity, the isolation of which is the object

of various research studies, which at the same time, establish novel biotechnological and

toxicological applications (Welker et al., 2006; Singh et al., 2011)

Finally, the antimicrobial and antibacterial activities of microalgal metabolites have

proved to be important. Chlorella has the ability to suspend the growth of Gram-positive

and Gram-negative bacteria. Antifungal agents are produced by Prorocentrum lima and

Amphidinium (Washida et al., 2006). Chaetoceros lauderi, and Dunaliella salina also have

proved to produce substances that affect various bacteria and fungi, such as Candida

albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Aspergillus

niger (Mendiola et al., 2008). D. salina acts against Klebsiella pneumonia, while

Dunaliella primolecta acts against Staphylococcus aureus and other bacteria, with great

antigrowth activity (Pane et al., 2015).

Besides their tremendous potential on the sectors of food and health, microalgae produce

certain secondary metabolites, the phycotoxins, with serious adverse effects. In fact, the

already identified species that produce toxins are classified as (Caruana and Amzil, 2018):

• non-toxic species, capable though of reaching higher levels of toxins by high

biomass producing (HABs), resulting in the destruction of marine fauna and anoxia;

• species that produce toxins, with the ability to harm the humans, through the food

chain;

• species toxic to fish or other aquatic organisms, through hemolytic toxins;

• toxic species with direct impact to human health through inhalation or skin contact.

During a toxicological assessment, the microalgal toxins are characterized as:

• biogenic, which means that they are synthesized by the species or formed by the

decomposition of the metabolic products, and therefore are considered part of the

organism, and

• non-biogenic, which are composed by environmental contaminants, and can be

avoided by certain cultivation methods and careful management of the biomass

production processes, selecting sites which are not near pollution.



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Hence, the biogenic toxins can be, under certain circumstances, the nucleic acids and

microalgae produced toxins, while the non-biogenic toxins are mostly about the

accumulation of heavy metals in the algal biomass (Becker, 2004).

The last 40 years, there have been observed increased incidents of toxicity, with

amnesic, diarrheic, and azaspiracid (AZA) poisoning through the consumption of fish. The

cause of the episodes is the anthropogenic factor, as the pollution and the climate change

are immensely connected with the microalgal toxic effect (Caruana and Amzil, 2018).

Especially the presence of industrial waste facilitates the development of toxic microalgae,

which spread and reproduce rapidly. The poisoning has been observed in the coasts of

Europe, Asia, South America, South Africa and Australia mostly by cyanobacteria (M.

aeruginosa, Anabaena and Aphanizomenon) which are hard to differentiate from non-toxic

species (Becker, 2004).

The Greek mainland, with 18.000 km of coastline, is one of the countries that suffer

from the effects of toxic algae. The anthropogenic factor has led to the increased nutrient

supply of the microalgae and cyanobacteria species, from terrestrial sources, which, on

their turn, have resulted in phenomena of fish mortality as well as red tides, due to the

development of high biomass producing species (harmful algal bloom, HAB). Occasional

records of microalgae samples in all major gulfs of the Greek coastline have proved the

presence of toxic and potentially toxic microalgal species. The majority of the toxic species

were observed in Thermaikos and Amvrakikos Bays (Ignatiades and Gotsis-Skretas, 2010;

Nikolaidis et al., 2005), mostly due to the continuous nutrient supply from the rivers and

the urban sewage system, resulting in great degradation of the marine biota and the water

quality.

The risks of toxicity in microalgae and cyanobacteria, have led to thorough examination

with the accumulation of toxicological data. When certain limits are reached in fish meat or

in other commercial products, there is direct impact on the sector, with economic loss and

skepticism from the consumers, retailers and wholesalers.



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Biofuels

Brennan and Owende (2010) refer to the requirements under which a biofuel resource has

the possibility to become a technologically and economically sustainable source. These are:

• To cost less than fossil fuels (in terms of production and harvest), or to be similarly

competitive;

• To require less or similar use of land;

• To facilitate improvement of the quality of the atmosphere (CO2 absorption);

• To consume minimum amounts of water;

• To be productive, by the selection of the most efficient strains, with high lipid levels

and high photosynthetic activity (for autotrophic microalgae).

The microalgal and cyanobacterial cultivation has the ability to meet the aforementioned

requirements and thus, constitute a crucial bioenergy source, with significant environmental

advantages (Wang et al., 2008). Furthermore, the potential of microalgae as a considerable

candidate for the production of biofuels, is their capability to produce polysaccharides and

triacylglycerides. These two compounds are among others, the ingredients of bioethanol

and biodiesel fuels (Carlsson et al., 2007).

The microalgal biomass, in order to produce various forms of biofuels, can be

technologically converted into thermochemical and biochemical conversion, chemical

reaction and direct combustion, as observed in Fig. 7 The selection of each type depends on

the type and the quantity of the biomass, the produced sort of energy (biogas, bio-oil,

biodiesel and bioethanol), economic factors, activity specifications and the desirable end-

product (McKendry, 2002).



-17-

The thermochemical conversion is one of the most common and feasible strategies

regarding biomass conversion but the most immediate way to produce biofuel from

microalgae is through Anaerobic Digestion, extracting biogas (Faried et al., 2017). Biogas,

with approximately 70% methane in its composition, regardless of the algal strain and the

operating factors, is therefore one of the most environmentally friendly and effective

biofuel in bioenergy production, reducing at the same time, the GHG emissions, in

comparison to the conventional fossil fuels (Fehrenbach et al, 2008).

Other significant biofuels include photobiologically produced biohydrogen as well as

bioethanol through fermentation (Frac et al., 2010).

The microalgal technology regarding the production of biofuels, depends on the

cultivation and harvest of the biomass. However, regarding biodiesel, the lipid content of

each microalgae species is an indicator but does not determine the total amount of the

biofuel yield (Mata et al, 2010). Table 3 is a representation of selected microalgae

feedstocks, which are currently used in biodiesel production and the oil contents they

report, expressed as a percentage of dry mass weight, while Table 4, compares the biodiesel

production from microalgae to other conventional plant-derived feedstock, in terms of oil

yield, use of land and biodiesel yield.

Figure 7 Microalgal biomass conversion processes and forms of energy obtained.

Modified from: Wang et al., 2008.



-18-

Table 3. Oil content of various microalgae species:

Microalgae Oil content (% dwt)

Botryococcus braunii 25–75

Chlorella sp. 28–32

Crypthecodinium cohnii 20

Cylindrotheca sp. 16–37

Dunaliella primolecta 23

Isochrysis sp. 25–33

Monallanthus salina >20

Nannochloris sp. 20–35

Nannochloropsis sp. 31–68

Neochloris oleoabundans 35–54

Nitzschia sp. 45–47

Phaeodactylum tricornutum 20–30

Schizochytrium sp. 50–77

Tetraselmis suecica 15–23

B. braunii 25–75

Modified from: Singh and Gu, 2010.

Table 4. Comparison of microalgae with other biodiesel feedstock:

Plant source

Seed oil

content (%

oil by wt in

biomass)

Oil yield

(L oil/ha

year)

Land use (m2

year/kg

biodiesel)

Biodiesel

productivity (kg

biodiesel/ha

year)

Corn/Maize (Zea mays L.) 44 172 66 152

Hemp (Cannabis sativa L.) 33 363 31 321

Soybean (Glycine max L.) 18 636 18 562

Jatropha (Jatropha curcas L.) 28 741 15 656

Camelina (Camelina sativa L.) 42 915 12 809

Canola/Rapeseed (Brassica Napus L.) 41 974 12 862

Sunflower (Helianthus annuus L.) 40 1070 11 946

Castor (Ricinus communis) 48 1307 9 1156

Palm oil (Elaeis guineensis) 36 5366 2 4747

Microalgae (low oil content) 30 58700 0.2 51927

Microalgae (medium oil content) 50 97800 0.1 86515

Microalgae (high oil content) 70 136900 0.1 121104

Modified from: Mata et al., 2010

From the comparison of the microalgal potential with other plant oil crops, the first to

notice is that the microalgal yields, depend on the strain and the oil content of each species.

However, despite the fact that the seed plants and microalgae have similar oil contents,

microalgae report significantly higher levels of oil yield than the rest of the vegetable crops.

This happens due to the fact that the microalgal production takes place throughout the year,



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and thus, it is logical for productivity levels to outpace every other oilseed crops (Schenk,

2008). As for the use of land, microalgae are at an advantage, with the considerably low

requirements per m2, per year. This advantage is also depicted on the annual biodiesel

production per hectare, which reports higher values even for strains with low oil content. At

all cases, microalgae are followed by the palm oil biodiesel, at clearly lower values.

Within the bioenergy market sector, the microalgae- based products can be allocated,

with the prediction that offer and demand for these commodities will increase substantially

in the near future. The energy sector, is characterized by relatively low market prices,

mostly referring to the fossil fuels. The total energy consumption for the EU-19 countries

was estimated to be about 1150 M Toe (tons of equivalents) in 2015, which corresponds to

about 500 billion € (European EnAlgae project, 2015). The sector comprises of three main

parts: electricity at 40%, transportation at 35% and heat at 25%. For heat and electricity,

biomethane (biogas) is targeted as a resource, while for transportation fuels the focus is on

biodiesel, bioethanol, biomethane (biogas) and alternatives for jet fuel.

Unfortunately, the total financial turnover from the exploitation of microalgae biomass in

the bioenergy market is significantly low. Biomethane has a selling price of 0.2 € m-3,

bioethanol is sold at 0.4 € kg-1 and biodiesel at 0.5 € L-1, which are not considered

prohibitively high, but with production costs of 20.5 € m−3, 33.34 € kg−1, 25.56 € L−1

respectively (European EnAlgae project, 2015), they are not considered feasible.

A number of potential microalgae-based products is identified in Table 5, which

describes their use and selling price. As observed, the prices from literature data (Barsanti

and Gualtieri, 2018) are not consistent and thus, Table 5 designates these variations.



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Table 5. Potential microalgae products, use and selling price

Product Use Selling price

€ Ton -1

Biomass Raw biomass Electricity 1000

Biomass Glycerol (byproduct from

biodiesel extraction)

Electricity 500

Biomass Nutrient rich biomass

(byproduct from biodiesel

extraction)

Biogas 200

Primary

metabolites

Lipids Biodiesel 500

Primary

metabolites

Polysaccharides (starch.

Oligomeric sugars)

Bioalcohol/

biohydrogen

400

Modified from Barsanti and Gualtieri, 2018

Cost-effective cultivation systems and methods, production, harvesting and biomass

concentration are one of the most important obstacles in the commercialization of the

microalgal products, as the costs are greatly high. As for the methods of microalgal biofuels

production, the majority of the companies is reported to cultivate microalgae in closed

systems, or use photobioreactors (PBR). Nevertheless, the natural establishments require

less capital allocation, reducing the costs. The open pond systems are an appealing choice

for districts where the microalgal cultivation is not expected to interfere with the food

chain, through excessive use of land (Singh and Gu, 2010). A bio-economic production

model which was proposed during the EnAlgae initiative, calculated the total investment

cost of an open and a closed cultivation system of 1 ha at the amount of 1.000.000 €, while

up-scaling to 100 ha would cost about 50.000.000 € in investment for both types of systems

(EnAlgae program, Spruijt et al., 2015). On the other hand, Ruiz et al. (2016) estimated an

investment cost of 50.000.000 € for open systems, 100.000.000 € for tubular PBR, and



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80.000.000 € for flat panel PBR, for an up scaling of 100 ha. Finally, Rösch et al. (2012)

admit that the production of microalgal biofuels are considerably higher than the traditional

biofuels, suggesting a price range of 1.94 € to 3.35 € per liter of algae biodiesel if favorable

assumptions and technological advancement are taken into consideration.

The economic viability of the biofuels industry, requires that every single primary

component of the microalgal and cyanobacterial biomass, from the proteins, carbohydrates

and fats to other organic and inorganic molecules, is converted into new output. The novel

end-products and their technologies will be dictated by the system efficiency and

effectiveness, as well as the cost of the raw material (Parmar et al., 2011). The feasibility of

the biofuel market is greatly enhanced if the production is parallel with high-value

byproducts, which would be promoted to the relevant markets, increasing the revenues and

sharing the production costs.

Apart from the product development, the biofuels production process could be combined

with environmental activities, such as the wastewater treatment and the CO2 bio-mitigation,

in order to ensure sustainability and cost-effectiveness.

Wastewater remediation

Van Harmelen and Oonk (2006) have supported that the production of biofuels, when

combined with wastewater treatment, is expected to be the most effective commercial

application of microalgae in the short term. For this reason, Muñoz and Guieysse (2006)

suggest procedures by which organic and chemical contaminants can be removed, along

with heavy metals and pathogens, during a wastewater remediation process at the same

time with the production of biomass aimed for biofuels. The main incentives for this

process are the reserves on the chemical compounds, because those substances act as

microalgal nutrients, as well as the environmental benefits which arise from the reduced

amounts of freshwater, supplying the biomass cultivation. Wastewater, with high levels of

CO2, is an exceptional growth medium, facilitating the production with high growth rates,

no need for nutrient input, reduced harvesting costs and elevated lipid content (Lundquist,

2008).



-22-

The major disadvantages are the increased land requirements of the algal plants, in cases

of open pond systems and the increased cost in capital, in cases of photobioreactor systems.

Examples reported in the international literature, regarding the use of microalgae in the

treatment of wastewater, include the use of Botryococcus braunii to remove nitrate and

phosphate (Sawayama et al., 1995), the use of Scenedesmus obliquus to remove phosphorus

and nitrogen (Martínez et al., 2000), at percentages of 98% for phosphorus and an

impressive 100% for ammonium. The same species was also used to dissolve nitrogen

concentrations in artificial wastewater (Gomez Villa et al., 2005). Chlorella vulgaris was

grown to achieve ammonia bioremediation (reported a rate of 0.022 g NH3 l−1 per day)

(Yun et al., 1997). Finally, the cyanobacterium Spirulina sp. during experimentation, acted

as a biosorbent, and was able to absorb heavy metal ions (Cr3+, Cd2+, and Cu2+) (Chojnacka

et al., 2005).

In the environmental applications of microalgae, their use in bioassays of environmental

pollutants is another advantage. Chlorella sp., Dunialella tertiolecta, Pseudokirchneriella

subcapitata, Scenedesmus quadricauda and Isochrysis galbana, contribute in the evaluation

of the presence of nitrogen and phosphorus in freshwater ecosystems (Vannini et al., 2011;

Ismail, 2004).

Bio-mitigation of CO2 emissions using microalgae

Microalgae captures carbon dioxide from three distinct sources: the atmosphere,

emissions from industrial and power generation processes and soluble carbonate. The first

source is the most common method and concerns the mass transfer of carbon to the

microalgal aquatic cultivations through photosynthesis (Wang et al., 2008). Nevertheless,

the reported atmospheric capture is low, due to low concentration of CO2 in the air

(360 ppm), factor that does not allow economic viability (Stepan et al., 2002). On the

contrary, emissions of flue gases of industrial or power plants have higher concentrations

(up to 20%) and additionally, both photobioreactor and raceway pond systems have the

ability to adapt to the process (Bilanovic et al., 2009). The drawbacks are that a limited

number of algae species are tolerant to such high levels of NOx and SOx, which exist in the

flue gases. It has been supported that the toxicity in the cultivation of microalgae rises



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dramatically, with high concentrations of NOx and SOx. Chlorella, for instance, when

exposed to NOx higher than 150ppm and Sox higher than 50ppm suffered high toxic effects

(Maeda et al., 1995). Finally, various microalgal strains accumulate CO2 from soluble

carbonates, such as NaHCO3 and Na2CO3.

Deciding on which microalgal strains to grow for CO2 bio-mitigation is crucial to the

efficiency and cost competency of the process. Microalgae which is cultivated in open

ponds and closed systems that use the atmospheric air, are less productive than cultivations

near industrial exhausts, with concentrations up to 15% of CO2. The last are regarded an

effective means of cultivation and subsequently, an efficient method for CO2 bio-

mitigation. In addition, the high salinity and pH values of the growth medium, facilitate the

control of unwanted species, as not many strains have the ability to survive in harsh

conditions (Wang et al., 2008). Microalgal strains, suitable for this process should

preferably have:

• significant growth and CO2 capture rates;

• tolerance in high levels of NOx and SOx;

• ability to produce valuable bioproducts;

• ability to contribute in wastewater treatment;

• easy harvest;

• tolerance of elevated water temperature in order to reduce costs of cooling flue

gases.

The above characteristics are not present in their totality, in any single microalgal strain.

However, selected species used for bio-mitigation are Chlorella sp. (Chlorella vulgaris,

Chlorella kessleri), Scenedesmus sp. (Scenedesmus obliquus), Botryococcus braunii,

Haematococcus pluvialis, Spirulina sp. (Brennan and Owende, 2010).

The high costs of the bio-mitigation process, compared with the high cost of microalgal

biofuel production, pose impediments in the commercial exploitation. Bio-mitigation of

CO2 emissions can only be regarded as an interdependent and integral part of the biofuels



-24-

production process, with the ability to reduce the cost, ensure sustainability and create

positive environmental impact.

Bioplastics

The struggle to become independent of the fossil fuels highlights the derivative need to

reduce the use of petrochemically produced plastics. While the global demand for plastic is

rising, pressurizing the current market conditions, significant environmental concerns arise,

with the accumulation of plastic in landfills and the marine ecosystems (Rahman, and

Miller, 2017). These concerns ignite, on their turn, international, national and local

initiatives, especially in the sector of packaging.

As an alternative to the petrochemicals, bio based plastics with biodegradable capability

can be proposed. The aforementioned can be classified as renewable- derived from natural

and renewable sources, petroleum-based but biodegradable and a mixture of the two

(Reddy et al., 2013).

Using microalgae to produce bioplastic would be a vehicle to capture CO2 directly from

the atmosphere, forming a polymer. The methods to convert microalgae to bioplastics vary

among the direct use of the biomass as a bioplastic, blending of the biomass with petroleum

plastics, transitional processing in biorefineries and genetic engineering techniques with the

aim of creating strains which produce bioplastics (Rahman, and Miller, 2017). Microalgae

and cyanobacterial derived bioplastics have been produced from Spirulina platensis,

Chlorella vulgaris, Nannochloropsis spp., Botryococcus Braunii etc. (Zeller et al., 2013;

Shi et al., 2012; Torres et al., 2015)

However, the use of microalgae for long-term production of bioplastics is not sustainable

(DiGregorio, 2009). Bioplastics are not yet cost-competitive in comparison to the

petroleum equivalents. Other models of production which could reduce the cost are

suggested to be the biorefineries or the simultaneous production of many product lines, to

enhance economic feasibility (Anthony et al., 2013; Trivedi et al., 2015).



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Cosmetics

The production of microalgae and cyanobacteria-consisting cosmetic products, enriched

with antioxidants and various other bioactive substances, is considered a growing and with

high potential sector. The need to create safe products, developed with environmentally

friendly bioprocesses, has classified microalgae as a sustainable source of bioproducts

(Michalak and Chojnacka, 2014).

Table 6 reports a variety of microalgae species and their contribution to the cosmetics

industry, through a plethora of applications, multiple for selected species:

Table 6. Microalgae and cyanobacterial applications in cosmetics

Microalgae and Cyanobacteria Commercial applications Ref.

Arthrospira and Chlorella Skin care products, hair care

and sun protection products

Ariede et al., 2017

Ascophyllumnodosum, Chlorella

vulgaris, Alaria esculenta,

Chondrus crispus, Mastocarpus

stellatus, Spirulina platensis,

Dunaliella salina

Anti-aging factors Wang et al., 2015

Chlorogloeopsis sp, Isochrisis,

Nannochloropsis , Fucus

vesiculosus, Nostoc sp.

Prevent photo-aging,

wrinkles formation and skin

sagging

Ariede et al., 2017

Porphyra, Spirulina sp. and

Chlorella sp.

Moisturizers for skin, hair,

face and body

Ariede et al., 2017

Thraustochytrium,

Aurantiochytrium and

Schizochytrium

Skin enhancement, with non-

toxic, non-irritating, and non-

sensitizing compounds

Ariede et al., 2017



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Microalgae and Cyanobacteria Commercial applications Ref.

Monodus sp., Thalassiosira sp.,

Chaeloceros sp., and

Chlorococcum sp

Anti-aging products that

intensify collagen stimulus

Ariede et al., 2017

Coccoid and Filamentous Skin photo-aging Ariede et al., 2017

Phaeodactylum tricornutum Skin elasticity and firmness Ariede et al., 2017

Chlamydocapsa sp. Photo-aging, products for

skin and hair protection

Ariede et al., 2017

Nannochloropsis oculata Skin whitening Ariede et al., 2017

Monodus sp., Thalassiosira sp.,

Chaeloceros sp. and

Chlorococcum sp.

Hair loss Ariede et al., 2017

The secondary metabolites that the microalgal species produce during cultivation, make

them an excellent natural source of these substances, with an important activity in

cosmetology (Ariede et al., 2017). Natural polysaccharides, such as carrageenans from red

algae, fucoidans from brown algae and ulvans from green algae, hydrating and moisturizing

minerals, antioxidants, carotenoids, anti-inflammatory compounds and antimicrobial

substances are abundant in the microalgal species and have been the object of scientific

observation in the production of cosmetics, as a potent and beneficial biotechnological

application (Wang et al., 2015).

Companies with activities related to microalgal biotechnology

The global interest on the technological and commercial application of all the possible

products which are derived from microalgae, can be observed through the table below.

Table 7 lists a few examples of biotechnological companies, which cultivate microalgae

and/or cyanobacteria and use the biomass for various purposes, along with their geographic

location, the species cultivated and the market to which they target and develop their

products.



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Table 7. List of algal biotechnological companies.

Country Company Microalgae and

Cyanobacteria

species

Market Internet Source

Nederland Algaebiotech Nannochloropsis,

Tetraselmis,

Heamatococcus

Pluvialis,

Isochrysis

Food supplements,

anti-aging creams,

aquaculture feed

http://www.algaebiotech.

nl/ France

Malaysia

Spain Algaenergy Spirulina,

Chlorella,

Dunaliella and

Haematococcus,

Nannochloropsis

gaditana,

Isochrysis

galbana

Aquaculture,

agriculture, food,

feed, natural

pigments,

cosmetics,

technology and

engineering

http://www.alga

energy.es/en/

France Algama Spirulina,

chlorella

Food and nutrition,

chemicals,

cosmetics

http://algamafoods.com/

Israel Algatech Haematococcus

Pluvialis

Food and beverage http://www.algatech.com

/

USA Algenol Spirulina Natural colorants,

protein, personal

care, soil treatment

http://algenol.com/sustai

nable-products/

Portugal Allmicroalgae Chlorella,

Nannochloropsis

sp.,Haematococc

us sp,

Scenedesmus sp.

Feed, food, beauty

care

http://www.allmicroalga

e.com/



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Cyanobacteria

species


Israel Aqwind

solutions

Microalgae Wastewater

treatment

http://aqwind.com/

Sweden AstaReal AB Microalgae Food supplements

and skin care

http://www.astareal.se/pr

oducts

Belgium B-Blue Spirulina Spirulina drink https://www.b-blue.com/

USA Cellana Microalgae Oils, animal feed,

and biofuel

feedstocks

http://cellana.com/contac

t-us/

Japan DIC Lifetec Spirulina Pharmaceutical,

food

http://www.dlt-spl.co.jp/

Japan Euglena Euglena Healthcare, energy

and environment

http://www.euglena.jp/

France Fermentalg Microalgae Oils and proteins https://labiotech.eu/indus

trial/fermentalg-first-

product-novel-food-

authorization/

Scotland GlycoMar Microalgae Healthcare and

personal care

Glycomar.com

USA Klamath

Algae

Products

Aphanizomenon Feed & Food http://www.klamathafa.c

om/

Norway MicroA Prasinococcus

capsulatus

Cosmetic and

healthcare purposes

https://microa.no/prasino

guard/

Japan Nikken

Sohonsha

Dunaliella Personal care http://www.nikken-

miho.com/

India Parry

Nutraceuticals

Spirulina,

Chlorella

Health

Supplements

http://www.parrynutrace

uticals.com/



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Cyanobacteria

species


USA Qualitas

Health

Microalgae Food and nutrition https://www.qualitas-

health.com/

Mexico Qualitas

Health

Sweden Simris Alg Microalgae Health ingredients

and premium

dietary

supplements

https://simrisalg.se/sv/

Germany Solaga Cyanobacteria Biogas https://www.solaga.de/

Switzerland SpirAlps Microalgae Food / Nutrition

Luxembourg SustainWater Microalgae Water treatment http://www.sustainwater.

lu/

Belgium TomAlgae Microalgae Aquaculture feed http://www.tomalgae.co

m/about/

Israel Univerve Microalgae Food, feed and bio-

based industries

https://www.univerve.co.

il/

Taiwan Wilson

Enterprise

Spirulina &

Chlorella

Feed & Food http://www.wilson-

groups.com/

China Xiamen

Huison

Biotech

Schizochytrium Health and

personal care

http://www.chinahuison.

com/en/index.aspx

France Greensea Microalgae Aquaculture,

pigments and

cosmetics

http://greensea.fr/

USA Earthrise Spirulina Food / Nutrition http://earthrise.com/

The websites were accessed on October 2018.



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SWOT Analysis

The SWOT analysis presented below, aims to investigate and analyze the strengths and

weaknesses, at the level of production and commercial application of microalgae and

cyanobacteria and their products. The prospects and risks of the technology used and the

future potential, must also be recorded and evaluated so that, combined with the strengths

and weaknesses, to allow an overview regarding the microalgae and cyanobacteria

technological and commercial applicability. The SWOT analysis developed and its

observations, are shown in Table 8:

Table 8. SWOT analysis on microalgae and cyanobacteria.

Strengths Weaknesses

-Easy cultivation, with no seasonal

restrictions, with the ability to grow with

absent or limited attention, providing water

not suitable for human consumption.

Ability to obtain the nutrients needed

(nitrogen, phosphorus, etc.) easily1.

-Can grow in areas not suitable for

agricultural activities, unaffected from

weather conditions and hostile

environments. Therefore, microalgae do

not cover arable land2.

-Cultivation does not require pesticides and

herbicides2.

-Microalgae grow rapidly, with exponential

growth rates1.

-Wastewater can be used as culture

medium without the need to use freshwater.

-The selection of microalgal species, must

balance the primary production with the

extraction of other valuable co-products in

order to achieve sustainability2.

-Not all species are suitable for different

regions/environments1.

-There are high production costs10.

-There is small scale production at the

present production systems, and therefore

there are2:

• Low yields in biofuel production.

• Low yields in bioproducts, such as

EPA and DHA.

-May not produce essential metabolites

naturally, or produce them only in very

small amounts.

-In biofuels production, there is the



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-Other substances can be extracted, besides

the aim of cultivation, depending on the

species, which have applications in other

industrial sectors, such as fine chemicals,

bioproducts and biomass3.

- Can improve the air quality, microalgae

can achieve biofixation of CO2 and

greenhouse gas emissions reduction2.

-Can contribute to the treatment of organic

waste which come from the agricultural

and food industry, using them as nutrients.

-Co- products of microalgae, after

fermentation, can produce ethanol or

methane and the remaining biomass can be

used as a new growth medium, rich in

nutrients10.

possibility of negative energy balance, due

to the harvesting and extraction techniques.

-The species which have wider commercial

applicability are only a few. In addition,

there is no large-scale production and

relevant data for better estimation and

assessment1.

-Microalgae tend to assimilate gases-

products of combustion. But even though

flue gases are used as nutrients, only a few

species can survive at higher

concentrations of NOx and SOx 1.

-Higher costs limit microalgae applications

to high-value markets, as human food and

aquaculture.

-The production systems need to advance

in order to achieve more efficient

photosynthetic activities.

Opportunities Threats

-Considerable investment over the last

years, increases production capacity and

commercial applicability of microalgae

based products4,8,9.

-Production cost of microalgae biomass can

be reduced further, with the advancement

in technology, especially when combined

with wastewater treatment5.

-Ability to enter low-value markets, such as

biofertilizers10.

-New technological developments are

needed in order to reduce evaporation and

CO2 dispersion losses, as well as grow

individual species1.

-Possible genetic modification of certain

microalgal strains could create regulatory

limitations and potential societal

disapproval and uncertainty2.

- The genetic modification of algae in order

to accomplish mass cultures with high oil



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-Due to the various high-valued biological

compounds microalgae can produce, and

their commercial application, they have the

potential to reform and remodel radically

the majority of biotechnological sectors,

such as pharmaceuticals, nutrition

additives, biofuels, cosmetics, pollution

treatment1.8,9.

- The biochemical composition of the

microalgae biomass has the ability to be

modified by alternating the conditions of

cultivation, and thus increasing the product

yields2.

-Microalgae has the ability to produce

biohydrogen11, which is regarded as a

"clean fuel", renewable and ecological, an

excellent substitute of fossil fuels.

-Genetic and metabolic engineering are

expected to increase dramatically the

performance of certain microalgal strains.

Scientific research has drawn attention to

the potential of transgenic microalgae as

green-cell factories which can produce

multiple products, such as biofuels,

proteins and metabolites or other high-

valued products7. 7

yields and high productivity rates, is not

required, as other organisms might be

found, which naturally have the

aforementioned characteristics or may

cause severe environmental consequences

if the modified algal strains are released in

the ecosystem6.

7 1.Gendy and El-Temtamy, 2013

2. Mata et al, 2010

3. Wang et al., 2008

4. Raja et al., 2008

5. Rosenberg et al., 2008



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Sustainability Evaluation of microalgae market sectors

The unique ability of microalgae and cyanobacteria to produce renewable energy, create

material resources, and have environmental effects via the greenhouse gases emissions

reduction and wastewater treatment, revolutionizes the research on microalgal organisms

(Reith et al., 2004). The multiple applications of each biomass production promote

sustainability, a crucial element in the sector of natural resources management, as well as

economic viability.

To move further, the sustainability of microalgal applications depends on technical,

environmental and socio-economic concerns and awareness. An assessment regarding the

food and biofuels categories is analyzed below. The food and energy industries are the ones

that draw attention in the field of microalgae research and the ones that are aided by

governmental and European funds, in order to develop initiatives, the first for the discovery

of new ways to feed the population and the second to reduce the dependency on fossil fuels

and the greenhouse gas emissions. Therefore, the present dissertation focuses on these two

sectors and a sustainability evaluation is attempted in order to assess the current market

situation.

6. Rodolfi et al., 2008

7. León-Bañares et al., 2004

8. Li et al., 2008 (a)

9. Li et al., 2008 (b)

10. Singh and Gu, 2010

11. Sharma et al., 2017



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Sustainability and Financial Evaluation of the Food Sector

The food industry faces the challenge of meeting the nutritional and dietary requirements

of the global consumers, struggling to formulate products with low levels of sugar and fat,

rich in fiber and proteins. Microalgae and cyanobacteria have a great potential in this

sector, to strengthen the nutritional value of the conventional food sources and contribute

positively to the improvement of human and animal health. The bioactive compounds,

molecules and natural ingredients that can produce are promising to future applications. In

fact, more than 75% of the annual microalgal biomass production is used for the

development of tablets, powder and capsules as a base to food products, with

unprecedented rate (Chacón-Lee and González-Mariño 2010). The most attractive and

common microalgal products are the ones used as dietary supplements (Molina et al.,

2003). However, there is need for diversification and use of the current biotechnological

advances in order to secure continuous progress (Liang et al., 2004).

A major scientific report, performed on behalf of the European Commission (Enzing et

al., 2014) lists information regarding the commercial exposition of products derived from

microalgae. The findings are shown in Table 9:



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Table 9. Market information on microalgae and cyanobacterial -derived products

Current product

based on

microalgae/cyanobacteria

Production

volume

(tonnes/year dry

weight)

Value of

production

volume

(annual

turnover)

Potential market

(synthetic / traditional

forms)

Food and feed products: whole dried microalgae biomass

Spirulina 5,000 tonnes/

year (2012)

US $ 40m

(2005) No synthetic alternative

Chlorella 2,000 tonnes/

year (2003)

US $38m

(2006) No synthetic alternative

Food and feed products: microalgae components

Astaxanthin (derived from

Haematococcus)

300 tonnes/year

(2004)

US $10m

(2004)

US$200m

(2004)

Phycibiliprotein

colourants (incl.

phycocyanin)

(NA) (NA) > US $ 50m

(2004)

EPA/DHA (Omega-3

PFA) (based on

Chrypthecodinium)

240 tonnes/year

(2003)

> US $300m

(2004)

±US 14.39bn

(2009)

β-Carotene (based

on Dunaliella Salina,

Schizochrytium,

Nannochloropsis)

1,200 tonnes per

year (2010) (NA)

US $ 285m

(2012)

Modified from: Enzing et al., 2014, European Commission

From the findings we observe that Spirulina and Chlorella are the market leaders in their

sector, with the largest reported volumes of production. Only a few companies seem to

develop microalgal products in general, especially in USA and Asia, with the exception of

Chlorella, whose production is allocated across a number of manufacturers. The

commercial potential of microalgae, considerable in the high-valued products, such as β-

carotene, astaxanthin, DHA and EPA, shows advantages over the conventional and

synthetic options, but microalgal products are still less competitive.



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The success in the microalgal food industry, is determined among other reasons, by the

ability to select the most efficient species, which possess the right characteristics for

cultivation and commercialization. This statement is reinforced by the successful

comparison of certain microalgal species to other food sources of Table 1. The rich content

in proteins, carbohydrates, amino acids and other fine chemicals is clearly evident of the

high biological value of the microalgae products.

Draaisma et al. (2013), in their study, summarize the most fundamental characteristics,

which can lead to economic sustainability in food production as well as a safe application

of the commodities derived by microalgae, as presented in Table 10.

Table 10. Food commodities from microalgae: overview of key features, which need to be

considered to enable successful sustainable, cost effective and safe product applications.

Production

technology

Sustainability

assessment

Safety

assessment

Oils and

Proteins

Product

application

•Photobioreactor

•Location

•Microalgal

species

•Water source

•Medium use

•Process strategy

•Down stream

processing

•Biorefinery

•Water use

•Land use

•Land use

change

•Medium use

•Eutrophication

•Global warming

•Energy demand

•Toxicological

data

•History of safe

use

•Triacylglycerides

•Fatty acid profile

•Function

•Health benefits

•Amino acid profile

•Solubility

•Function

•Health benefits

•Taste

•Appearance

•Colour

•Nutrition

•Structure

•Processability

•Stability

•Consumer

acceptance

Modified from: Draaisma et al, 2013.

The microalgae biomass can be difficult to commercialize in the food industry as the

odor, distinct green color, sharp fishy taste and powdery texture can prove at least

inconvenient to consume. For this reason, research should focus on the enhancement in

sight, taste and smell of the microalgal products. On the other hand, the incorporation of

microalgae and cyanobacteria in the nutritional habits, is also a matter of culture. In areas



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of the world, such as China and Asia, where the traditional diet consists of seafood and

other similar products, the negative characteristics are considered favorable. The western

countries, regard microalgae as a radical ingredient, novel and in cases not acceptable

(Liang et al., 2004).

The situation is different with the use of microalgae and cyanobacteria for purposes of

biomolecule extraction, where their consumption as natural additives and supplementations

is gaining interest. In Germany, France, Japan, USA and Thailand, biotechnological

companies perform activities for the commercialization of microalgae in yogurt, bread,

pasta and beverages. The pharmaceutical and cosmetic companies are aligned to this

approach, in order to create novel product lines (Gantar and Svircev, 2008). However, a

large scale commercial production of bioproducts, has to defeat several financial and

industrial obstacles and impediments, in order to achieve higher product yields. For this

reason, improvement in certain areas are necessary, as for example, screening and careful

selection of more productive strains, culture development and new harvest and extraction

methods and technologies (Pulz and Gross 2004).

Finally, the most important drawbacks, other than the economic feasibility, have to do

with the safety assessment from the corresponding regulatory authorities. The toxicological

evaluation of the microalgal novel food products, is an essential process in order to affirm

clearly and officially that they are safe for human consumption.

Toxicological tests are used to prove that the examined products are harmless, especially in

the cases of unconventional food sources, as are microalgae. Apart from the safety of the

microorganism, the presence of heavy metals, hazardous pathogens, formed by-products

and possibility of natural formation of toxins should also be evaluated. Becker (2007)

stated that the microalgae products currently used in the food industry, do not report any

side effects, even at human trial levels, and therefore they are safe and can be further

utilized for future applications. However, the available data and information from currently

exploited microorganisms and specific species, are needed to develop safer toxicity tests

and identify possible inconsistencies.



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Sustainability Evaluation of the Biofuels Sector

The most important microalgae and cyanobacterial application other than food is the

production of biofuels. It has been reported that biofuels derived from microalgae, are not

cost effective and cannot compete with the existing fossil fuels, without the support of

governmental subsidies or private funding. Current research trends are focused on turning

microalgal biofuels into an economically viable solution, having also in mind the decline in

crude oil reserves and the increasing price per barrel (Torrey, 2008).

The perception that microalgal fuels can be environmentally sustainable and economically

viable can be established by the examination of the (Aquafuels, 2018):

• energy and carbon balance,

• environmental impacts and

• cost of production.

For the feedstock production to be feasible, it is crucial that the energy levels and carbon

footprint are desirable. Such estimation is the object of life cycle assessment (LCA)

methods, which analyse and measure the inputs and outputs of the production process. The

major drawback of this concept is the lack of large-scale industrial production in the field

of microalgal biofuels. As a result, any data available is derived from laboratory

cultivations or commercial productions of other high-valued products, such as food

supplements and pigments. Other limitations include poor LCA input data in the form of

erratic system boundaries and functional units, as well as inconsistent methodologies, so

that no valid assumptions can be made; as for the scientific assumptions, their accuracy and

transparency are dubious (Slade and Bauen, 2013). On the other hand, LCA studies have

shown that in basic production systems that include only the cultivation, harvest and

extraction processes, significant energy levels are required and therefore, it is indicated that

microalgal production could be more efficient in the development of products other than

energy. Finally, if the energy and nutrients required have high CO2 emissions, then the

production could be equivalent to the conventional biodiesel emissions (Slade and Bauen,

2013; Gendy and El-Temtamy, 2013).



-39-

The environmental impacts can be valued by several criteria. First of all, a low-cost water

supply is crucial for the sustainability of the biofuels production. Freshwater could be

replaced by sea or brackish water. The last though would require special treatment in order

to remove unwanted substances which impede the microalgal growth, increasing at the

same time the energy required for production (Darzins et al., 2010). Water recycling can

decrease the water consumption and the subsequent nutrient depletion but could increase

the risk of infection from bacteria, viruses and fungi, which are present in recirculated

waters, along with metabolites and chemicals from previous processes. Therefore, water

needs to be removed in order to eliminate unwanted pollutants. The distance to the water

source is also crucial, mostly in terms of energy consumption and selection of cultivation

locations (Lundquist et al., 2010).

As mentioned before, for the cultivation of microalgae, nutrients, such as nitrogen and

phosphorus are needed. The use of fertilizers cannot be prevented, especially if we consider

that the dry biomass contains almost 7% nitrogen and 1% phosphorus. Wijffels and

Barbosa (2010) argue that if the EU replaced the present transportation fuels with algal

biofuels, it would demand almost 25 million tons of nitrogen and 4 million tons of

phosphorus per year. These amounts are double than the current European volume of the

production of fertilizers (K. van Egmond et al., 2002).

On the other hand, and in small scale production systems, recycled nutrients from

wastewater would have the ability to limit the inflow, incorporating the wastewater

treatment in the biofuels production. On-going production systems already regard the

recycling of nutrients as a crucial factor of the production design and operation (Lundquist

et al., 2010).

CO2 is an essential factor in the cultivation process. As for the impact of the carbon

dioxide fertilization, carbon affects radically the system's energy balance. CO2 could be

introduced either by the inflow of flue gases directly to the system or by separation from

the flue gas, following an energy consuming process. It is more desirable to use directly the

flue gases, as long as the species can endure the presence of contaminants (Slade and

Bauen, 2013). The presence of conventional fossil fuels in the production of microalgal

biofuels is in the form of electricity consumption during the various steps of the process



-40-

and, in some cases, in natural gas for the biomass drying. The controlling of the

temperature, could also increase the need for fossil fuels, whereas there are various

environmental strategies to reduce it, such as the use of heat from power generation and

optimization of the production systems to decrease energy needs (Acién et al., 2012).

Finally, the cost of production can measure the expenditure of each step of production

and the contribution to the overall cost, providing valuable information to the future studies

and their design. Such assessments though, appear to have limitations, comparable to the

life cycle assessments (LCA) drawbacks, which mostly include lack of data and strong

dependence on parameters and assumptions which apply to laboratory-scaled cultivations.

In addition, current reviews on microalgal productions, estimations, carbon dioxide capture

and system designing reflect prospective ambitions other than current results (Slade and

Bauen, 2013). The ability of co-product harvesting has also important effect on the

economic feasibility of a microalgal biomass production.

The contribution of microalgae in Bioeconomy and Circular Economy

Since 2012, the European Union has adopted a Bioeconomy Strategy and Action Plan

according to which five main challenges are identified, towards which actions are planned

and executed (European Commission review, 2017). Those are:

• food security

• sustainable management of natural resources

• reduce independence on non-renewable sources

• mitigation and adaptation to climate change

• job creation and EU competitiveness.

Bioeconomy is based on sustainability. Incorporated into the above five key challenges, is

the aim to achieve sustainability with environmental extension to carbon neutral production

and reinforcement of the industrial factor with ecological but cost-effective value chains

and processes. Furthermore, the aim is to achieve sustainability in ecosystem restoration,



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from marine ecosystems which are polluted by plastic to land degraded ecosystems and

their restoration.

The Bioeconomy strategy, is parallel to the conceptual framework of circular economy.

According to the European Commission (2015) circular economy can be implemented in

various stages of the product life cycle, the most important of which regard the production,

consumption and waste management.

The product design, as well as the processes regarding production, has a great impact on

saving resources, recycling and the subsequent waste generation. The great environmental

and social impacts of the sustainable sourcing, in a European and global level, highlight the

need to take measures which will refer to every industrial sector. As for the consumption,

the consumers select their preferences according to the relevant information they have, the

level of the prices in comparison to existing alternatives and the flexibility of the legislative

instrument. However, the central idea of circular economy is the waste management. This

notion has two dimensions. The first has to do with the need to reduce the amount of

material that ends up in landfills or is incarcerated in order to protect the environment and

prevent further economic loss. The second supports the concept that recycled and reused

materials can be injected back into the production process, in the form of raw materials and,

for this reason, the waste management practices are greatly important.

The above two strategic formation of the European Union are interconnected and

interdependent. As expressed in the Commission's Expert Group on Bio-based Products

Final Report (2017) "policies and supportive measures should aim to ensure the creation of

a bioeconomy which uses bio-based resources in a circular way (circular bioeconomy)".

Their collaboration can ensure the more productive and efficient use of resources. The

updated Bioeconomy Strategy (2018) is in accordance towards this idea, as "to be

successful, the European bioeconomy needs to have sustainability and circularity at its

heart". Achieving this will accomplish reformation of the industry, modernization and

remodeling of the production processes, and environmental preservation.

At this landscape, bioproducts are expected to have a crucial role in the progression of the

current linear economic models to the more sustainable, "zero-waste", innovative and

efficient circular economy (Commission's Expert Group on Bio-based Products, 2017).



-42-

Therefore, the unique abilities of the microalgal biomass can be used to propose a

sustainable business model, based on the principles of circular economy and considering

microalgae as a renewable source.

The sustainable microalgal business model, as proposed in Fig 8 consists of three

stakeholders, the biomass production enterprise, at the phase of cultivation, the product

development enterprise, at the phase of bio-based product development and the waste

management and recycling enterprise at the phase of re-use and recycling of the remaining

material.

Figure 8 Proposed sustainable microalgae business model



-43-

The implementation of the proposed business model can serve to a great extent in the

totality of the key challenges of Bioeconomy and circular economy, as provisioned in the

strategic planning of the European Union. Tables 11 and 12 summarize the practical

applications of microalgae, which give them the ability to successfully fulfil the criteria set

by the European Union:

Table 11. European Union action plan for Bioeconomy and the contribution of microalgae

and cyanobacteria

Bioeconomy Challenges Microalgae and cyanobacteria practical

applications

➢ Sustainable development ✓ Microalgae is a renewable resource,

able to promote sustainability.

➢ Food security

✓ Microalgae has a huge potential as a

source of food, being more productive,

without the need of agricultural land

and the use of pesticides, only water

supply. Also the variety of products

and co-products which can be

extracted are extremely valuable to the

human organism.

➢ Sustainable management

of natural resources

✓ Microalgae as a renewable, recyclable

and biodegradable resource,

contributes to the principles of circular

economy and bioeconomy. Also, the

use of the waste as raw materials can

increase the revenues of the

stakeholders.



-44-

Bioeconomy Challenges Microalgae and cyanobacteria practical

applications

➢ Reduce independence on

non-renewable sources

✓ Microalgae biomass is a renewable

energy source, with the ability to

produce biofuels.

➢ Mitigation and adaptation

to climate change

✓ Microalgae captures effectively CO2

and contributes to the reduction of

greenhouse gas emissions. Also, the

development of bioplastics can

contribute to the environmental

protection.

➢ Job creation and EU

competitiveness.

✓ Microalgae stakeholders can benefit

from their business activities, through

European funding and support.

Table 12. European Union action plan for Circular economy and the contribution of

microalgae and cyanobacteria

Circular Economy Challenges Microalgae and cyanobacteria

practical applications

➢ Production ✓ CO2 absorption in order to

produce biomass.

✓ Ability to create bio-products.

➢ Product design ✓ Energy efficient products,

recyclable, upgradable and

durable, as stated in the

Ecodesign Directive (2009).



-45-

Circular Economy Challenges Microalgae and cyanobacteria

practical applications

➢ Product processes ✓ Ability to use wastewater as a

source of nutrients and ability

to purify wastewater for

human consumption.

➢ Consumption ✓ Various applications: food/

feed, biofuels, bioplastics,

cosmetics, fine chemicals.

Ecological products result in

biodegradation, leading to

recycled, reduced waste.

➢ Waste management ✓ As proposed before, with

wastewater treatment and

recycling of bio-products to

provide the necessary nutrients

for cultivation and reduce

waste. Also the use of

microalgal bioplastics could

contribute with their

biodegradable capabilities.

➢ Waste to resources, secondary

raw materials and water reuse

✓ The biomass created is used for

product development.

✓ The bio-products are

recyclable.

✓ The human activity, with the

use of bio-products, creates

ecological waste.

✓ The wastewater is used again

and can be cleared.



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The proposed business model constitutes a sustainable suggestion on how microalgae can

be industrialized and contribute with their multiple applications and abilities to European

and global concerns, which are complex and multidimensional. However, in economic

terms, economies of scale are an important factor in the production and market exploitation

of the microalgae-based products. The high amounts required as fixed capital combined

with the labor costs leave small room for competitive prices and efficient average cost of

per kg dry weight mass. The European Union seems to acknowledge this impediment and

at the latest updated Bioeconomy strategy (2018) prioritizes the intensification and up-

scaling of the bio-based sectors and markets, including microalgae, the encouragement of

local bioeconomies across the member states and promotes a better communication of the

ecological principles of bioeconomy.



-47-

Conclusions

Microalgal and cyanobacterial biotechnology has emerged because of the diversity of the

products that the algal biomass can develop. The ambiguous future that unfolds ahead with

the food and energy deficiency, in comparison with the climate change, leads to the

microalgal biomass examined as an alternative to the emerging problems encountered.

The variety of industrial and commercial uses of microalgae and cyanobacteria in the

fields of nutrition, health, biofuels, cosmetics, pharmaceuticals and environmental

protection, emphasize their high potential as a renewable source and their importance in

biotechnology. The fast and easy cultivation, combined with their advantages as sources of

bioactive compounds with many biological activities (antioxidant, antiviral, antibacterial,

anti‐inflammatory) and their ability to supply food and renewable energy have increased

the global interest in the relevant fields of research.

However, regarding the food sector, the low capacity in production of human food derived

from microalgae, leads the global market to consider it as an unrealistic solution, as the

biomass is not adequate for large scale food production, especially in comparison to other

conventional feedstock, as vegetables and cereals, which are accessible in large quantities.

In order to overcome this issue, more efficient production systems need to be designed,

with the contribution of the technological advancements. Considerable reduction of the

production cost can be achieved with the parallel retrieval of nutrients from residuals, while

producing biomass. The advancements in the sector of food, should be supported by

biotechnological breakthroughs and development of more efficient and with improved

biochemical composition microalgae strains.

On the other hand, sustainability in the microalgal production of biofuels also appears to

be far from being achievable. Technological advancements and environmental challenges

can leave room of improvement and large-scale production systems. The diversity that the

various species of microalgae show is prone to invent new applications and commercial

products. With more accurate estimations and experience gained over the years, with

innovation combined with economic feasibility and, more importantly, with active

engagement of important public and private stakeholders, the necessary investment and



-48-

practical implementation of the microalgal applications would overcome the current

challenges and the microalgal industry would develop viably.

To exploit at the greatest extent the future potential of the microalgae biotechnological

applications, areas of improvement could be considered the following:

• Cost-effective microalgae biomass production, which could be achieved with

systems requiring efficient amounts of input energy, new growth mechanisms and

conditions, as well as constant annual production of biomass;

• Effective recovery of the biomass, with novel drying mechanisms, dewatering

processes with the highest possible preservation of the important biomolecules and

research on ways to ensure stability of the microalgal substances;

• Technological and biotechnological advancements, to develop novel products,

establish new methods of processing the biomass and preservation of the bioactive

compounds and fine chemicals, produced at the microalgae cultivation;

• Environmental sustainability, with specific provisions on the energy required for the

cultivation and harvest, combined with wastewater treatment application, water

recirculation and CO2 mitigation;

• Safety regulations, regarding the safety or possible harmful effects of certain

microalgae species, the production processes as well as the potential side effects of

the products or the bio-products;

• Focus on the potential of microalgae as a source of bioactive substances, with the

relevant research on extraction and safety;

• Finally, the most demanding challenge has to do with the consumers and the

commercial application of the microalgal products, where, especially on food

sector, improvement strategies should be adopted to promote and enhance the

chemical properties and quality of the final product, ameliorating the odor, flavor

and colour. As for the other sectors, the end-user should be fully informed on the

characteristics and attributes of the novelty and be reassured, from the scientific

community and the appropriate regulatory bodies, about the safety, harmlessness

and efficiency of the product of interest.



-49-

The challenges are many to overcome in order to reach viable, economically feasible and

sustainable solutions regarding the full- scale exploitation of microalgae. But the huge

potential of these microorganisms has driven many scientists all over the world to search

for inventive answers to the problems and ways to unfold the microalgal capabilities.



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