Enhanced photo‐bioelectrochemical energy conversion by genetically engineered cyanobacteria. Issue 3 (18th September 2015)

• Record Type: Journal Article
• Authors: Sekar, Narendran; Jain, Rachit; Yan, Yajun; Ramasamy, Ramaraja P.
• Is Part Of: Biotechnology and bioengineering. Volume 113:Issue 3(2016)
• Page Start: 675
• Page End: 679
• Publication Date: 2015-09-18
• Subjects: Synechococcus elongatus -- outer membrane cytochrome -- photocurrent -- extracellular electron transfer -- genetic engineering -- photosynthetic microbial fuel cell; Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.25829
• Languages: English
• ISSNs: 0006-3592

Abstract

ABSTRACT: Photosynthetic energy conversion using natural systems is increasingly being investigated in the recent years. Photosynthetic microorganisms, such as cyanobacteria, exhibit light‐dependent electrogenic characteristics in photo‐bioelectrochemical cells (PBEC) that generate substantial photocurrents, yet the current densities are lower than their photovoltaic counterparts. Recently, we demonstrated that a cyanobacterium named Nostoc sp. employed in PBEC could generate up to 35 mW m −2 even in a non‐engineered PBEC. With the insights obtained from our previous research, a novel and successful attempt has been made in the current study to genetically engineer the cyanobacteria to further enhance its extracellular electron transfer. The cyanobacterium Synechococcus elongatus PCC 7942 was genetically engineered to express a non‐native redox protein called outer membrane cytochrome S (OmcS). OmcS is predominantly responsible for metal reducing abilities of exoelectrogens such as Geobacter sp. The engineered S. elongatus exhibited higher extracellular electron transfer ability resulting in approximately ninefold higher photocurrent generation on the anode of a PBEC than the corresponding wild‐type cyanobacterium. This work highlights the scope for enhancing photocurrent generation in cyanobacteria, thereby benefiting faster advancement of the photosynthetic microbial fuel cell technology. Biotechnol. Bioeng. 2016;113: 675–679. © 2015 Wiley Periodicals, Inc. Abstract : The cyanobacterium Synechococcus elongatus PCC 7942, upon genetic engineering to express a non‐native redox protein called outer membrane cytochrome S (OmcS), exhibited higher extracellular electron transfer ability resulting in approximately ninefold increase in photocurrent generation than the corresponding wild‐type cyanobacterium. The novel strategy adopted in this work highlights the scope for enhancing photocurrent generation using cyanobacteria, thereby enabling rapid advancement of the photo‐bioelectrochemical energy conversion technology.