Macroalgae and their potential for biofuel.

Abstract Green technologies are in demand worldwide to meet the fuel needs of the increasing population together with combating global warming. Although biofuels from conventional energy crops and lignocellulosic biomass can substitute for fossil fuels, there is much controversy over questions raised regarding impacts on food supply and security and their cost effectiveness. A high photosynthetic efficiency and production rate confer algae with attractive credentials for third-generation biofuels. Algae (both microalgae and macroalgae) represent an economical and environmentally sustainable renewable source of biomass for the production of biofuels. Algal biofuels are attractive in that they do not compromise food supplies and arable land. Microalgae have hitherto received more attention than macroalgae. Nevertheless, the latter can also serve as a viable option for biofuel generation. Carbohydrates obtained from macroalgal biomass can be used for fermentative production of bioethanol. Macroalgal biomass can store large amounts of oil which can be exploited for the production of biodiesel. Methane and hydrogen can readily be produced from macroalgal biomass through biologically mediated degradation. The biorefinery approach, integrating bioprocessing and low-environmental-impact chemical technologies, would be more pertinent in effecting maximum and efficient utilization of macroalgal biomass through the generation of diverse products from a single biomass feedstock. This review encompasses the potential and prospects of macroalgae as sources for biofuels and the role of biorefinery approach in invigorating macroalgal fuel economy.