Genetically Engineered Cyanobacteria Enhances Photocurrent Generation in Photo-bioelectrochemical Cell.

Cyanobacteria exhibit light dependent exoelectrogenic activity in photo-bioelectrochemical cells (PBEC) generating substantial photocurrent. However compared to the other competing technologies such as photovoltaics, the photocurrent generated by cyanobacteria is lower and is not suitable yet to become a viable alternative technology. Initiatives to understand and enhance the exoelectrogenicity of cyanobacteria are crucial to resolve this caveat. In this perspective, a cyanobacterium named Synechococcus elongatus PCC7942 was genetically engineered to express a heterologous protein called outer membrane cytochrome S for enhancing its exoelectrogenicity. The genetically engineered cyanobacteria exhibited nearly 9 fold higher photocurrent generation than the corresponding wild-type cyanobacterium. Further, power density generated by the genetically engineered cyanobacteria in a rudimentary PBEC was found to be five times higher than that generated by wild-type. The multidisciplinary research work presented here highlights the scope for enhancing photocurrent generation by cyanobacteria thereby benefiting faster advancement of PBEC technology.