AUTHOR=Kong Guannan , Song Da , Guo Jun , Sun Guoping , Zhu Chunjie , Chen Fusheng , Yang Yonggang , Xu Meiying 

TITLE=Lack of Periplasmic Non-heme Protein SorA Increases Shewanella decolorationis Current Generation

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00262

DOI=10.3389/fmicb.2020.00262

ISSN=1664-302X

ABSTRACT=<p>Bacterial extracellular electron transport (EET) plays an important role in many natural and engineering processes. Some periplasmic non-heme redox proteins usually coexist with <italic>c</italic>-type cytochromes (CTCs) during the EET process. However, in contrast to CTCs, little is known about the roles of these non-heme redox proteins in EET. In this study, the transcriptome of <italic>Shewanella decolorationis</italic> S12 showed that the gene encoding a periplasmic sulfite dehydrogenase molybdenum-binding subunit SorA was significantly up-regulated during electrode respiration in microbial fuel cells (MFCs) compared with that during azo-dye reduction. The maximum current density of MFCs catalyzed by a mutant strain lacking SorA (Δ<italic>sorA</italic>) was 25% higher than that of wild strain S12 (20 vs. 16 μA/cm<sup>2</sup>). Both biofilm formation and the current generation of the anodic biofilms were increased by the disruption of <italic>sorA</italic>, which suggests that the existence of SorA in <italic>S. decolorationis</italic> S12 inhibits electrode respiration. In contrast, disruption of <italic>sorA</italic> had no effect on respiration by <italic>S. decolorationis</italic> S12 with oxygen, fumarate, azo dye, or ferric citrate as electron acceptors. This is the first report of the specific effect of a periplasmic non-heme redox protein on EET to electrode and provides novel information for enhancing bacterial current generation.</p>