richest sources of vitamin B12 . Its nutritional efficiency as a dietary supplement has
been the subject of many studies with positive results [232, 235]. Although toxicity
studies indicate that Arthrospira consumption did not exhibit any toxicity [236], in
recent years, in some countries there have been concerns regarding the potential
toxicity and long-term effects on human health. Thus, there is strict legislation for
microcystin and other toxins of Arthrospira biomass destined to be dietary supplement, and this restricts the marketing of the whole algal biomass [237]. However, its
global sell value has continued to expand. The global market size which was
estimated to be around USD 348 million in 2018 is projected to reach USD
779 million by 2026 [238].
Arthrospira biomass has served as highly nutritious feed for many agriculturally
important animals. Studies made using Arthrospira biomass as chicken, pig, cattle,
rabbit, and sheep feed resulted in encouraging results that show better animal
growth, nutritional product quality, fertility, and aesthetic values [239].
Arthrospira is also known for producing an array of bioactive compounds with
antioxidant, anticancer, antibacterial, antifungal, and antiviral activities [240]. This
makes it one of the favored nutraceuticals and cosmetic ingredient which in turn
significantly contributed to the market expansion. Further purification and characterization of the bioactive substances are necessary to determine if there is any novel
substance of interest for drug development.
Alkaliphiles are known for their fast and dense growth, and these alkaliphilic
cyanobacteria make the East African soda lakes the most productive ecosystems
[188]. In addition to its productivity, Arthrospira can be easily and cheaply cultivated in open pond systems. In non-alkaline cultivations, cultures crash due to
microbial contamination and predators [241, 242]. On the other hand, the alkaline
growth condition mitigates culture crashes by preventing the growth of contaminants
and predators as mentioned above in Sect. 4.8. Thus, considering that alkaliphilic
cyanobacteria are fast growers, nutritious, produce a range of useful bioactive substances, and easily grow outdoor, it seems rewarding to deeply study and evaluate
their potential in not only food and feed applications but also as sources of bioactive
substances. One interesting study area could be to isolate toxin-free strain or
metabolically engineer it to be toxin-free to ease the restrictions in some countries
and raise consumers’ confidence, which may be a step for further expansion of the
market.
4.10 Alkaliphiles in Bioelectricity: Microbial Fuel Cell
Generation of electrical energy from renewable organic matters contained in biomass
has begun attracting attention. One means of generating bioelectricity is through
microbial fuel cells (MFCs). In MFCs, microorganisms oxidize organic or inorganic
substrates and generate current which can be tapped as sustainable energy. The
electron generated during the oxidation of substances will be attracted to the terminal
(anode) of the microbial fuel cell which subsequently move to the positive terminal
30
G. Mamo and B. Mattiasson
been the subject of many studies with positive results [232, 235]. Although toxicity
studies indicate that Arthrospira consumption did not exhibit any toxicity [236], in
recent years, in some countries there have been concerns regarding the potential
toxicity and long-term effects on human health. Thus, there is strict legislation for
microcystin and other toxins of Arthrospira biomass destined to be dietary supplement, and this restricts the marketing of the whole algal biomass [237]. However, its
global sell value has continued to expand. The global market size which was
estimated to be around USD 348 million in 2018 is projected to reach USD
779 million by 2026 [238].
Arthrospira biomass has served as highly nutritious feed for many agriculturally
important animals. Studies made using Arthrospira biomass as chicken, pig, cattle,
rabbit, and sheep feed resulted in encouraging results that show better animal
growth, nutritional product quality, fertility, and aesthetic values [239].
Arthrospira is also known for producing an array of bioactive compounds with
antioxidant, anticancer, antibacterial, antifungal, and antiviral activities [240]. This
makes it one of the favored nutraceuticals and cosmetic ingredient which in turn
significantly contributed to the market expansion. Further purification and characterization of the bioactive substances are necessary to determine if there is any novel
substance of interest for drug development.
Alkaliphiles are known for their fast and dense growth, and these alkaliphilic
cyanobacteria make the East African soda lakes the most productive ecosystems
[188]. In addition to its productivity, Arthrospira can be easily and cheaply cultivated in open pond systems. In non-alkaline cultivations, cultures crash due to
microbial contamination and predators [241, 242]. On the other hand, the alkaline
growth condition mitigates culture crashes by preventing the growth of contaminants
and predators as mentioned above in Sect. 4.8. Thus, considering that alkaliphilic
cyanobacteria are fast growers, nutritious, produce a range of useful bioactive substances, and easily grow outdoor, it seems rewarding to deeply study and evaluate
their potential in not only food and feed applications but also as sources of bioactive
substances. One interesting study area could be to isolate toxin-free strain or
metabolically engineer it to be toxin-free to ease the restrictions in some countries
and raise consumers’ confidence, which may be a step for further expansion of the
market.
4.10 Alkaliphiles in Bioelectricity: Microbial Fuel Cell
Generation of electrical energy from renewable organic matters contained in biomass
has begun attracting attention. One means of generating bioelectricity is through
microbial fuel cells (MFCs). In MFCs, microorganisms oxidize organic or inorganic
substrates and generate current which can be tapped as sustainable energy. The
electron generated during the oxidation of substances will be attracted to the terminal
(anode) of the microbial fuel cell which subsequently move to the positive terminal
30
G. Mamo and B. Mattiasson