8.7.13 Microalgae: An ideal Source for Stable Isotope Compounds
Microalgae by the process of photosynthesis are able to incorporate various stable
isotopic compounds such as
2 H,
13 C, and
15 N from other inexpensive inorganic
compounds such as
2 H 2 O,
13 CO 2 , and
15 NO 3 . These stable compounds then form
other essential organic compounds such as carbohydrates, lipids, amino acids, and
nucleic acids. These stable isotopic biochemicals are used in two ways: first, they are
used to determine the atomic structures by incorporation into proteins,
carbohydrates, and nucleic acids, and second, they are used in the metabolic studies
(Spolaore et al. 2006).
8.7.14 Miscellaneous Applications of Microalgae
Microalgae can also be converted into biogas (Montingelli et al. 2015), bio-oil,
syngas, jet fuel, and fertilizers. Bio-oil a synthetic liquid fuel directly used in engines
or in a blend is extracted by processing biomass at high temperature in the absence of
oxygen (Demirbas 2006). Syngas contains very low concentrations of hydrocarbons
and higher concentrations of carbon monoxide and hydrogen generated by oxygen
gasification processes (Zhu et al. 2014). It can be converted into diesel fuel by
Fisher–Tropsch synthesis process, thus making it possible to integrate algal feedstock into the existing thermochemical infrastructure. Microalgae-derived jet fuel
has also received attention (Ghasemi et al. 2012) and is compatible for use in
selected commercial jet test flights (Zhu et al. 2014). Many agents that play the
role of modifying viscosity in various foods and pharmaceutical products are also
obtained from different types of seaweeds. Alginate, carrageenan, and agar are some
examples of such hydrocolloid compounds (Barrow and Shahidi 2008; Mata et al.
2010). Lastly, the use of algae in the agricultural fields as biofertilizers is also a
common practice. Algae are used as soil conditioners as they have the potential to fix
large amount of nitrogen, thus making the soil fertile (Song et al. 2005; Mathimani
et al. 2018; Renuka et al. 2018).
8.8
Limitation and Future Prospect
The microalgae have numerous applications; however, it has certain limitations:
first, algal strain should be carefully selected, and the production of biomass should
be enhanced. The desired strain can then be improved by lipidomics, genomics,
proteomics, and metabolomics which will have higher growth rate and lipid production and broader tolerance to environmental stresses and have the ability to produce
many valuable coproducts (Schenk et al. 2008; Singh et al. 2011). The specific
characteristics of algal strains can be modified through genetic engineering methods
with an intended alternation of the algae cells, thereby improving the production of
algal feedstock for biofuel (Tabatabaei et al. 2011; Adeniyi et al. 2018) and be
efficiently applied in both natural and artificial methods of cultivation. Thus, with the
8 Algal Biomass: Potential Renewable Feedstock for Biofuels Production – Part I
229
Microalgae by the process of photosynthesis are able to incorporate various stable
isotopic compounds such as
2 H,
13 C, and
15 N from other inexpensive inorganic
compounds such as
2 H 2 O,
13 CO 2 , and
15 NO 3 . These stable compounds then form
other essential organic compounds such as carbohydrates, lipids, amino acids, and
nucleic acids. These stable isotopic biochemicals are used in two ways: first, they are
used to determine the atomic structures by incorporation into proteins,
carbohydrates, and nucleic acids, and second, they are used in the metabolic studies
(Spolaore et al. 2006).
8.7.14 Miscellaneous Applications of Microalgae
Microalgae can also be converted into biogas (Montingelli et al. 2015), bio-oil,
syngas, jet fuel, and fertilizers. Bio-oil a synthetic liquid fuel directly used in engines
or in a blend is extracted by processing biomass at high temperature in the absence of
oxygen (Demirbas 2006). Syngas contains very low concentrations of hydrocarbons
and higher concentrations of carbon monoxide and hydrogen generated by oxygen
gasification processes (Zhu et al. 2014). It can be converted into diesel fuel by
Fisher–Tropsch synthesis process, thus making it possible to integrate algal feedstock into the existing thermochemical infrastructure. Microalgae-derived jet fuel
has also received attention (Ghasemi et al. 2012) and is compatible for use in
selected commercial jet test flights (Zhu et al. 2014). Many agents that play the
role of modifying viscosity in various foods and pharmaceutical products are also
obtained from different types of seaweeds. Alginate, carrageenan, and agar are some
examples of such hydrocolloid compounds (Barrow and Shahidi 2008; Mata et al.
2010). Lastly, the use of algae in the agricultural fields as biofertilizers is also a
common practice. Algae are used as soil conditioners as they have the potential to fix
large amount of nitrogen, thus making the soil fertile (Song et al. 2005; Mathimani
et al. 2018; Renuka et al. 2018).
8.8
Limitation and Future Prospect
The microalgae have numerous applications; however, it has certain limitations:
first, algal strain should be carefully selected, and the production of biomass should
be enhanced. The desired strain can then be improved by lipidomics, genomics,
proteomics, and metabolomics which will have higher growth rate and lipid production and broader tolerance to environmental stresses and have the ability to produce
many valuable coproducts (Schenk et al. 2008; Singh et al. 2011). The specific
characteristics of algal strains can be modified through genetic engineering methods
with an intended alternation of the algae cells, thereby improving the production of
algal feedstock for biofuel (Tabatabaei et al. 2011; Adeniyi et al. 2018) and be
efficiently applied in both natural and artificial methods of cultivation. Thus, with the
8 Algal Biomass: Potential Renewable Feedstock for Biofuels Production – Part I
229