make use of organic wastes, and also can be able to produce important products like
omega-3 fatty acids, carotenoids, protein-rich supplements, etc. [2].
Algae by acting as green cell factories are having the ability to transform light,
nutrients, and CO 2 into numerous compounds of high monetary value [3]. Due to
their high CO 2 sequestering ability and good solar conversion, algae can produce
more amounts of biomass and metabolites when compared with terrestrial plants [4].
Microalgae are wide set of aquatic organisms flourishing in different environments like sea water, fresh water, and saline conditions. Many algal strains that are
viable industrially are extremophiles; i.e., they can able to adapt and grow in intense
ecological conditions like salt pans (high salinity, e.g., Dunaliella sp. [5]), polar
regions (psychrotolerant, e.g., Koliella antarctica [6]), alkaline waters (Spirulina
sp.), high-nutrient wastewaters (Chlorella sp., Scenedesmus sp., Monoraphidium
sp. [7]), etc. The ability of algae to survive in polluted environments having rich
nutrients (nitrogen, phosphorus, potassium), the high tolerance of them to some
greenhouse gases like CO 2 , SOx, NOx, etc., makes them appealing, and they can
able to potentially transform organic wastes to biofuel and other value-added
bioproducts. The way of simultaneous waste treatment and production of biomass
is called “integrated cultivation process” [7].
Majority of the algae are phototrophic performing solar to chemical conversion
via photosynthesis. The key advantage of microalgae is that they have shown ability
to synthesize high lipid content, which then can be transformed into biodiesel.
However, the key bottleneck is high costs when microalgae are employed as energy
source.
For long microalgae are known to produce macromolecules like proteins, carbohydrates, and lipids; hence it has been utilized as a potential stock in the manufacture
of industrially valuable co-products. Different products used in cosmetics, food, and
feed industries like polysaccharides, pigments, and hydrocarbons/lipids can be
produced from microalgal biomass by altering the processing techniques (Fig. 1).
Microalgal lipids can potentially be converted into biofuels, polyols, polymers,
and specialty lipids like polyunsaturated fatty acids (PUFAs). Pigments like
phycobiliproteins, carotenoids can be utilized as natural colorants and sterols for
the production of steroids, nutraceuticals. The starch, glucans, and other complex
polysaccharides can be utilized for production of bioethanol, biofuel additives, and
bioplastics [8]. The defatted algal biomass produced after extraction of metabolites
might find its applications in biogas generation, animal feed, or can be used as
absorbent in removing synthetic dyes [9]. Thus total algal biomass can be converted
to worthy co-products.
The key steps involved in biofuels production and other value-added products
from microalgae are screening (identification of potential strain), cultivation (algal
growth in media by providing required nutrients), harvesting (separation of biomass), and post-harvest processing (extraction of products from biomass) (Fig. 2).
Algal Biomass for Biofuels and Bioproducts
141
omega-3 fatty acids, carotenoids, protein-rich supplements, etc. [2].
Algae by acting as green cell factories are having the ability to transform light,
nutrients, and CO 2 into numerous compounds of high monetary value [3]. Due to
their high CO 2 sequestering ability and good solar conversion, algae can produce
more amounts of biomass and metabolites when compared with terrestrial plants [4].
Microalgae are wide set of aquatic organisms flourishing in different environments like sea water, fresh water, and saline conditions. Many algal strains that are
viable industrially are extremophiles; i.e., they can able to adapt and grow in intense
ecological conditions like salt pans (high salinity, e.g., Dunaliella sp. [5]), polar
regions (psychrotolerant, e.g., Koliella antarctica [6]), alkaline waters (Spirulina
sp.), high-nutrient wastewaters (Chlorella sp., Scenedesmus sp., Monoraphidium
sp. [7]), etc. The ability of algae to survive in polluted environments having rich
nutrients (nitrogen, phosphorus, potassium), the high tolerance of them to some
greenhouse gases like CO 2 , SOx, NOx, etc., makes them appealing, and they can
able to potentially transform organic wastes to biofuel and other value-added
bioproducts. The way of simultaneous waste treatment and production of biomass
is called “integrated cultivation process” [7].
Majority of the algae are phototrophic performing solar to chemical conversion
via photosynthesis. The key advantage of microalgae is that they have shown ability
to synthesize high lipid content, which then can be transformed into biodiesel.
However, the key bottleneck is high costs when microalgae are employed as energy
source.
For long microalgae are known to produce macromolecules like proteins, carbohydrates, and lipids; hence it has been utilized as a potential stock in the manufacture
of industrially valuable co-products. Different products used in cosmetics, food, and
feed industries like polysaccharides, pigments, and hydrocarbons/lipids can be
produced from microalgal biomass by altering the processing techniques (Fig. 1).
Microalgal lipids can potentially be converted into biofuels, polyols, polymers,
and specialty lipids like polyunsaturated fatty acids (PUFAs). Pigments like
phycobiliproteins, carotenoids can be utilized as natural colorants and sterols for
the production of steroids, nutraceuticals. The starch, glucans, and other complex
polysaccharides can be utilized for production of bioethanol, biofuel additives, and
bioplastics [8]. The defatted algal biomass produced after extraction of metabolites
might find its applications in biogas generation, animal feed, or can be used as
absorbent in removing synthetic dyes [9]. Thus total algal biomass can be converted
to worthy co-products.
The key steps involved in biofuels production and other value-added products
from microalgae are screening (identification of potential strain), cultivation (algal
growth in media by providing required nutrients), harvesting (separation of biomass), and post-harvest processing (extraction of products from biomass) (Fig. 2).
Algal Biomass for Biofuels and Bioproducts
141