Department of Biotechnology, Centre for Research and Post Graduate Studies, Indian Academy Degree College, Bangalore 560043, Karnataka, India


Around 70% of the total global energy requirement is represented by fuels, and finding sufficient supplies of energy for the future is one of the most daunting challenges. Fluctuating oil prices, increasing gaseous emissions and their effect on green house, climatic change, and global warming stresses the urgent need to find new feedstocks for fuels. Biofuels promote environmental sustainability in terms of non-toxic, clean energy with a consequent decrease in greenhouse effect. Microalgae offer great promise to contribute a significant portion of the renewable fuels due to their higher photosynthetic activity, biomass productivity, CO2 fixation, O2 production, faster growth rate than higher plants, and ability to grow in non-arable land unsuitable for agricultural purposes. The properties of biodiesel from microalgal oil in terms of density, viscosity, acid value, and heating value are comparable to those of fossil fuels. However, prior to industrial scale application, a series of key challenges have to be resolved. The capital costs to transform microalgal biomass into biofuel are high and face a broad range of grand challenges to become technologically and economically viable. A systematic approach and process integration are critical factors in a successful future for algal bio-refineries. This chapter presents views and opinions on key technical challenges associated with microalgal culture system, cultivation conditions, growth medium, strain selection for highest growth rate, increased biomass productivity integrated with CO2 capture, lipid accumulation with adequate composition, and extraction methods.