and then dumping in landfill, compositing, or incineration. But these algal blooms
which are disposed off as waste can be valorized industrially to increase their
original value.
Algae has been identified as an untapped source of value-added products like
biofuel, food supplement, pigments, adsorbent, fertilizer, biogas, cosmetics, etc.
Usually these algae are cultivated in-house in monitored culturing conditions
because of the safety of the end use, especially in cosmetic, pharmaceutical, and
food industries. Nevertheless, the algal bloom which grows in mixed cultures of wild
condition cannot be used for such purposes, but it can be processed to products like
biochar, biooil, and biogas and as an adsorbent which have market value and are
subtly outlined in this review.
2 Algal Bloom Valorization
Algae both microalgae and macroalgae have vast potential application in industries
like food, pharmaceutical, water treatment, nutraceutical, textile, and energy [25–
29]. New applications are surfacing in recent years in industries like agriculture,
polymer, construction, solar cells, and printing inks [30–32]. Nevertheless,
researchers all over the world will accept algae to have enormous market potential
in terms of its application. Algae are usually cultured by providing the required
nutrient medium and light energy to produce value-added products which have huge
market base. But very less attention which is evident from the few research papers
showcases the possibility of converting the annoying algal bloom to value-added
products like their cultured counterparts. Algal bloom can be valorized by technical
processing like pyrolysis, compositing, fermentation, solvent extraction, and gasification to products of higher value than the original algal bloom since the algal
composition like lipids, carbohydrates, proteins, etc. remains more or less the same.
2.1 Biogas
Biogas having a composition of methane, carbon dioxide, and traces of nitrogen,
hydrogen, oxygen, and hydrogen sulfide is a renewable energy source for electricity,
thermal, and transport fuel which can also be stored and utilized [33, 34]. The algal
biomass is subjected to anaerobic digestion where the end products are obtained after
hydrolysis, acidogenesis, acetogenesis, and methanogenesis of the raw materials.
Microbial consortium is added to facilitate faster breakdown of substrates. Algal
biomass can be used as such or can be codigested with other organic substrates for
the production of biogas. Biogas was produced by anaerobic digestion of blue algae
which was skimmed from Taihu Lake, China, which reported a yield of
189.89 mL g
À1 VS
À1 with a methane concentration in the biogas as 36.72%
[35]. Biogas was produced by codigestion of corn straw and Taihu Lake blue
Valorization of Waste Algal Boom for Value-Added Products
131
which are disposed off as waste can be valorized industrially to increase their
original value.
Algae has been identified as an untapped source of value-added products like
biofuel, food supplement, pigments, adsorbent, fertilizer, biogas, cosmetics, etc.
Usually these algae are cultivated in-house in monitored culturing conditions
because of the safety of the end use, especially in cosmetic, pharmaceutical, and
food industries. Nevertheless, the algal bloom which grows in mixed cultures of wild
condition cannot be used for such purposes, but it can be processed to products like
biochar, biooil, and biogas and as an adsorbent which have market value and are
subtly outlined in this review.
2 Algal Bloom Valorization
Algae both microalgae and macroalgae have vast potential application in industries
like food, pharmaceutical, water treatment, nutraceutical, textile, and energy [25–
29]. New applications are surfacing in recent years in industries like agriculture,
polymer, construction, solar cells, and printing inks [30–32]. Nevertheless,
researchers all over the world will accept algae to have enormous market potential
in terms of its application. Algae are usually cultured by providing the required
nutrient medium and light energy to produce value-added products which have huge
market base. But very less attention which is evident from the few research papers
showcases the possibility of converting the annoying algal bloom to value-added
products like their cultured counterparts. Algal bloom can be valorized by technical
processing like pyrolysis, compositing, fermentation, solvent extraction, and gasification to products of higher value than the original algal bloom since the algal
composition like lipids, carbohydrates, proteins, etc. remains more or less the same.
2.1 Biogas
Biogas having a composition of methane, carbon dioxide, and traces of nitrogen,
hydrogen, oxygen, and hydrogen sulfide is a renewable energy source for electricity,
thermal, and transport fuel which can also be stored and utilized [33, 34]. The algal
biomass is subjected to anaerobic digestion where the end products are obtained after
hydrolysis, acidogenesis, acetogenesis, and methanogenesis of the raw materials.
Microbial consortium is added to facilitate faster breakdown of substrates. Algal
biomass can be used as such or can be codigested with other organic substrates for
the production of biogas. Biogas was produced by anaerobic digestion of blue algae
which was skimmed from Taihu Lake, China, which reported a yield of
189.89 mL g
À1 VS
À1 with a methane concentration in the biogas as 36.72%
[35]. Biogas was produced by codigestion of corn straw and Taihu Lake blue
Valorization of Waste Algal Boom for Value-Added Products
131