Algal biofuels: Technological perspective on cultivation, fuel extraction and engineering genetic pathway for enhancing productivity

Vast utilization and subsequent depletion of fossil fuels have forced to development of new approaches for finding a suitable alternative to fossil fuels. Algae remain a promising tool for producing third generation biofuels such as biodiesel, biohydrogen, bioethanol, etc and make them suitable material for bioenergy production. However, commercial application of biofuels from algal species is restricted due to cost for production, limitations in cultivation and harvesting and processing. This review focuses on various types of biofuels such as biodiesel, biohydrogen, bioethanol and biogas from different algal species utilizing cultivation systems such as raceway ponds and photobioreactors. The challenges in producing biofuels from native algal species are defined for finding alternative approach. This paper also focuses on the genetic engineering approaches available for modifying the pathway in algal species for increasing biomass and biofuel production. Metabolic activity can be enhanced using biochemical engineering. Hence the combined application of these approaches can help to take over the demerits of producing biofuels using algae. The cost required for biofuel production depends on the type of algal cultivating system and its challenge remains in harvesting and separation processes after cultivation.