Biodiesel from Microalgae

As the world’s population is increasing at an unprecedented rate, causing a severe impact on the limited and depleting petroleum reserves by their overexploitation and consumption. It is estimated that due to increasing socioeconomic and infrastructural advancements, we have already consumed about 50% of the petroleum reserves. Furthermore, the excessive usage of fossil fuels is believed to be a potential cause of global warming and a threat to environmental sustainability. This made the researchers to explore and study renewable and carbon-neutral sources of energy, which can be optimized as per the requirement and should be economically viable. Microalgae stand out momentous and materialized as feedstocks to get all that we need at a single platform. Microalgae are the primary producers that utilize CO2 and light for their growth. They can be grown in freshwater, saline water, and even in wastewaters due to their disparate biochemical metabolism. This urged the microalgae to be promoted for biorefinery approaches; it has the following significant features: potential for CO2 fixation; high biomass growth rate; its capacity to store carbon in lipids and carbohydrates to produce biofuels (bioethanol, biodiesel, biohydrogen, and biomethane) and recovery of various value-added metabolites (pigments, polysaccharides, antioxidants, and biopolymers). This led to the advent of microalgal biofuels as a green alternative to fossil fuels. It is then visualized, studied, and reported that microalgal biomass can be efficiently processed to biofuels, exclusively talking about biodiesel. This chapter provides an insight to the biotechnological progress made to exploit various microalgal taxonomical species to attain biodiesel. The chapter gives detailed discussion on the different methods of transesterification. The chapter gives an in-depth account to achieve biodiesel from microalgae in an economically and environmentally sustainable manner.