AUTHOR=Yang Jiani , Zhao Dan , Liu Tao , Zhang Shuang , Wang Weidong , Yan Lei , Gu Ji-Dong 

TITLE=Growth and genome-based insights of Fe(III) reduction of the high-temperature and NaCl-tolerant Shewanella xiamenensis from Changqing oilfield of China

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1028030

DOI=10.3389/fmicb.2022.1028030

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>A facultative anaerobe bacterium <italic>Shewanella xiamenensis</italic> CQ-Y1 was isolated from the wastewater of Changqing oilfield in Shaanxi Province of China. <italic>Shewanella</italic> is the important dissimilatory metal-reducing bacteria. It exhibited a well potential application in biodegradation and bioremediation.</p></sec><sec><title>Methods</title><p>Genome sequencing, assembling and functional annotation were conducted to explore the genome information of CQ-Y1. The effect of temperatures and NaCl concentrations on the CQ-Y1 growth and Fe(III) reduction were investigated by UV visible spectrophotometry, SEM and XRD.</p></sec><sec><title>Results</title><p>Genomic analysis revealed its complete genome was a circular chromosome of 4,710,887 bp with a GC content of 46.50% and 4,110 CDSs genes, 86 tRNAs and 26 rRNAs. It contains genes encoding for Na<sup>+</sup>/H<sup>+</sup> antiporter, K<sup>+</sup>/Cl<sup>−</sup> transporter, heat shock protein associated with NaCl and high-temperature resistance. The presence of genes related to flavin, Cytochrome <italic>c</italic>, siderophore, and other related proteins supported Fe(III) reduction. In addition, CQ-Y1 could survive at 10% NaCl (w/v) and 45°C, and temperature showed more pronounced effects than NaCl concentration on the bacterial growth. The maximum Fe(III) reduction ratio of CQ-Y1 reached 70.1% at 30°C without NaCl, and the reduction reaction remained active at 40°C with 3% NaCl (w/v). NaCl concentration was more effective than temperature on microbial Fe(III) reduction. And the reduction products under high temperature and high NaCl conditions were characterized as Fe<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>, FeCl<sub>2</sub> and Fe(OH)<sub>2</sub>.</p></sec><sec><title>Discussion</title><p>Accordingly, a Fe(III) reduction mechanism of CQ-Y1 mediated by Cytochrome <italic>c</italic> and flavin was hypothesised. These findings could provide information for a better understanding of the origin and evolution of genomic and metabolic diversity of <italic>S. xiamenensis</italic>.</p></sec>