ABSTRACT

Major sources of energy that drive the world are fossil fuels. Fossil fuel reserves are declining at a fast rate, and burning of these fuels also contributes to increased production of greenhouse gases leading to global warming. us, fossil fuels are considered to be unsustainable. In order to meet the environmental and economic sustainability, renewable, carbon-neutral fuels are necessary. Biofuels are suggested to be a good alternative for sustainable development. Competition with food crops leading to increase in food prices and lack of suitable and economical technology has hampered the use of rst-generation and second-generation biofuels by developing countries. Nowadays, microalgal biofuels are considered to be exible energy source for sustainable development. Algae-based biofuels are technically and economically viable and cost competitive, require no additional land, require minimal water use, and mitigate atmospheric CO2. Microalgae can be mass produced in raceway ponds or photobioreactors (PBRs). To reduce the cost of biomass production, microalgae can also be grown in wastewater that has the advantage of treatment of wastewater as well. Microalgal biomass may be harvested by occulation, centrifugation, ltration, and otation. Harvested biomass is then dried by sun or by freeze, drum drying, oven drying, or spray drying. Dried biomass is subjected to biofuel production such as biodiesel, biomethane, bioethanol, and biohydrogen. e viability of microalgal biodiesel production can be achieved by designing advanced PBRs and developing low-cost technologies for biomass harvesting, drying, and oil extraction. Commercial microalgal biodiesel production can also be accomplished by employing genetic engineering strategies to improve microalgal strains capable of withstanding environmental stress conditions and by engineering metabolic pathways for high lipid production. Biodiesel is a sustainable fuel, as it is available throughout the year and can be used to run any engine. Bioethanol from microalgae is a good alternative to bioethanol from food grains. Microalgal residue aer the extraction of lipids or starch can be used for the production of biomethane. Microalgal biofuels can satisfy the energy needs of future generations.