Maneuvering the genetic and metabolic pathway for improving biofuel production in algae: Present status and future prospective

The current energy demands continuously lead us to the quest of developing alternative energy sources to compete with the depleting fossil fuel reserves. In the recent years algae have garnered attention as third generation biofuel. However, low biomass concentration and metabolite accumulation results in low biofuel yield, thereby limiting its application. The present study reviews three possible approaches for enhancing biofuel production from algae: biochemical engineering, genetic engineering and application of omics/metabolic flux. Biochemical engineering depends on changing different physiological conditions such as increasing cultivation temperature or applying nitrogen stress to route the carbon flux towards metabolite accumulation. Genetic engineering exploits the knowledge of the major molecules for metabolite accumulation to create recombinant microalgal strains, which overexpresses specific enzymes or blocks certain pathways to improve metabolism of targeted biomolecules. Omics and flux analysis helps to mathematically analyze these manipulations and interpret different possible responses in silico, based on which experiments can be conducted in-vivo. Currently biochemical engineering is the most recognized technique for metabolite improvement in algae. However, these approaches have inhibitions which can be reduced by genetic engineering, metabolic flux or omics strategies. It was analyzed that integration of these approaches may help us to overcome the current limitations of algal biofuel production. The present paper discusses the merits, success rates and constraints of each of these approaches. The article explicitly discusses how combining these engineering techniques may help us to enhance the starch/carbohydrate and the lipid content in algae for establishing it as a promising energy feedstock for the future.