Table of Contents

ABSTRACT

Energy is considered to be the life line of an economy, vital instrument of socioeconomic growth and has been accepted as one of the most essential strategic commodities. The energy crisis is spinning out of control, at the same time the world is faced with a major development crisis.
Current energy source fossil fuel is widely recognized to be unsustainable due to their peak production and can be predicted to be exhausted in the future. Fuel from renewable sources is widely considered to be one of the most sustainable alternatives to fossil fuel and a viable means for environmental and economic sustainability. In this context microalgae are currently being promoted as an ideal source of biofuel because of their rapid growth rate, CO2 fixation ability and high production capacity.Innovative approaches towards clean energy development are vital as whole world looks for ways to reduce global warming, pollution and dependency on fossil fuels. Driven by population, development and industrialization, demand for primary energy and food is increasing at an unprecedented pace. Fossil fuel consumption cannot sustain the growing energy demand for much longer, and existing renewable energy sources are still unable to offer scalable competitive alternatives. Increasing food production requires arable land and fresh water but the intensive use of fertilizers produced from non-renewable energy resources returns us again to the energy challenge. In the context of global energy crisis, microalgal biofuel has core advantages over mineral fuel in that it is renewable, biodegradable, clean-burning, non-toxic and carbon neutral with respect to carbon dioxide related climate change. Microalgae are being used for the renewable production of several bioenergy carriers, including starch for ethanol, lipid for diesel fuel surrogates and H2 for fuel cells, which proved as a potential source of biofuels. Also microalgae have a higher photosynthetic efficiency, grow rapidly and utilize non-arable land, non-potable water, waste streams and do not compete with world agriculture market. It can produce up to 72% of starch and 80% of cellular storage lipids in the form of triacylglycerols (TAGs), which can be readily converted to biofuel via a simple conversion method. Biofuel obtained from these microalgae can burn with zero emissions of both air pollutants and greenhouse gases. This book chapter discusses the current knowledge of different techniques for production of microalgal biofuel like, biohydrogen through biophotolysis, biodiesel via trans-esterification of the lipids and bioethanol via fermentation of sugar depending on the species as well as the bio-refinery approach.