An Indian scenario on renewable and sustainable energy sources with emphasis on algae

Abstract

India is the fifth largest primary energy consumer and fourth largest petroleum consumer after USA, China, and Japan. Despite the global economic crisis, India's economy is expected to grow at 6 to 8 %/year. There is an extreme dependence on petroleum products with considerable risks and environmental issues. Petroleum-derived transport fuels are of limited availability and contribute to global warming, making renewable biofuel as the best alternative. The focus on biogas and biomass-based energy, such as bioethanol and biohydrogen, will enhance cost-effectiveness and provide an opportunity for the rural community. Among all energy sources, microalgae have received, so far, more attention due to their facile adaptability to grow in the photobioreactors or open ponds, high yields, and multiple applications. Microalgae can produce a substantial amount of triacylglycerols as a storage lipid under photooxidative stress or other adverse environmental conditions. In addition to renewable biofuels, they can provide different types of high-value bioproducts added to their advantages, such as higher photosynthetic efficiency, higher biomass production, and faster growth compared to any other energy crops. The viability of first-generation biofuels production is, however, questionable because of the conflict with food supply. In the future, biofuels should ideally create the environmental, economic, and social benefits to the communities and reflect energy efficiency so as to plan a road map for the industry to produce third-generation biofuels.

Biomass from Microalgae: An Overview

“…Algae are cultivated not only for food source but also the cultivated biomass is used for feedstocks too [6] and scaling up algae farming could lead to yields of other commercially viable products [7,8]. Since two thirds of earth's surface is covered with ocean, algae would be the option with greatest potential for food including aquaculture industries, pharma products and global energy needs ( Figure 1) [9].…”

Recent Advances in Feedstock and Lipase Research and Development towards Commercialization of Enzymatic Biodiesel

“…Lipids from microalgal origin appear as the most promising third-generation biodiesel feedstock. Microalgae have very high growth rates and accumulate high levels of lipids (oil) through photosynthesis [104,105]. Algal cultivation is easier than plant cultivation.…”

Cultivation of Oily Microalgae for the Production of Third-Generation Biofuels

“…It is reported that, apart from biodiesel a microalgae biorefinery can produce various other biofuels such as biohydrogen, biogas, bioethanol, etc. Hemaiswarya et al [56] reported that microalgal biomass residue after lipid extraction can also be reused for methane production. Microalgae biomass remaining after lipid extraction can also be potentially used as feedstocks in food, feed, pharmaceutical, and cosmetic industries, etc., as shown in Figure 4 [56][57][58].…”

“…Hemaiswarya et al [56] reported that microalgal biomass residue after lipid extraction can also be reused for methane production. Microalgae biomass remaining after lipid extraction can also be potentially used as feedstocks in food, feed, pharmaceutical, and cosmetic industries, etc., as shown in Figure 4 [56][57][58]. There is limited applicability of such processes due to costly processes but the utilization of lipid-extracted microalgae biomass (LEMB) to produce different energy sources along with the extraction of high value-added products will make the microalgal biorefinery approach more inventive and economically plausible.…”