2. CO₂ Sequestration Through Algal Biomass Production

The world is facing the threat of global warming. This is associated with the modernization and increasing dependency of human beings on the fossil fuel. Fossil fuel are necessary for providing the increasing demand on energy. However, their combustion produces greenhouse gases such as carbon dioxide, methane, ozone, NO_x, water vapour etc. (Kumar K et al., Bioresour Technol 102(8):4945–4953, 2011). CO₂ is also continuously being added into the earth’s atmosphere through several natural sources such as volcanic eruptions, combustion of organic matters, autotrophic and heterotrophic respiration (Kumar K, Das D, Carbon dioxide sequestration by biological processes. In: Bhanage BM, Arai M (eds) Transformation and utilization of carbon dioxide. Springer, Heidelberg, pp 303–334, 2014; Sharma A et al., Enzyme Microb Technol 48:416–426, 2011). However, robust natural mechanisms of CO₂ capture could maintain the balance of CO₂ in the earth’s atmosphere. Global carbon cycle is disturbed mainly due to anthropogenic emissions of CO₂ because of human activity (Kumar K, Das D, Carbon dioxide sequestration by biological processes. In: Bhanage BM, Arai M (eds) Transformation and utilization of carbon dioxide. Springer, Heidelberg, pp 303–334, 2014). Coal is the major contributor of CO₂, which is in the range of 14–17 % depending upon its quality. Therefore, coal-based industries such as cement, steel and thermal power plants pollute the earth’s environment to a greater extent.