Enhanced lipid productivity approaches in microalgae as an alternate for fossil fuels – A review

Abstract

Renewable energy sources especially biofuel is the focus in energy field. Microalgae have rapid biomass production and high oil content which is a promising oil producing alternative for fossil fuels and oil based crops. Changes in algal lipid production and composition have been attributed to variations in environmental and culture conditions. Stressful environmental conditions change the use of carbon uptake by algae for proliferation to energy storage in the form of oil. Fatty acids and triacylglycerols are energy storage compounds in microalgae accumulated under nutrient deprivation and stress conditions. The balance between maximum biomass and lipid production against the culturing conditions will be the ultimate goal of biofuel production from algae. Identification of suitable approaches for triggering algal lipid biosynthesis and lipid accumulation opens the door for enhanced lipid production with absolute quality and quantity of algae based fuels. This review lays the foundation for lipid induction strategies in microalgae to accelerate the application of algal biofuels as an alternate of fossil fuels for sustainable environment. Of the various approaches discussed, the one most often considered is that of nutrient limitation. Given the limitations of nutrient influenced lipid production, identifying other feasible approaches like CO2 influence, temperature, salinity and heavy metal stress will reduce the negative impacts of existing approaches thereby to obtain maximum microalgal lipid production.