Shewanella sp. O23S as a Driving Agent of a System Utilizing Dissimilatory Arsenate-Reducing Bacteria Responsible for Self-Cleaning of Water Contaminated with Arsenic

Abstract

The purpose of this study was a detailed characterization of Shewanella sp. O23S, a strain involved in arsenic transformation in ancient gold mine waters contaminated with arsenic and other heavy metals. Physiological analysis of Shewanella sp. O23S showed that it is a facultative anaerobe, capable of growth using arsenate, thiosulfate, nitrate, iron or manganite as a terminal electron acceptor, and lactate or citrate as an electron donor. The strain can grow under anaerobic conditions and utilize arsenate in the respiratory process in a broad range of temperatures (10–37 °C), pH (4–8), salinity (0%–2%), and the presence of heavy metals (Cd, Co, Cr, Cu, Mn, Mo, Se, V and Zn). Under reductive conditions this strain can simultaneously use arsenate and thiosulfate as electron acceptors and produce yellow arsenic (III) sulfide (As2S3) precipitate. Simulation of As-removal from water containing arsenate (2.5 mM) and thiosulfate (5 mM) showed 82.5% efficiency after 21 days of incubation at room temperature. Based on the obtained results, we have proposed a model of a microbially mediated system for self-cleaning of mine waters contaminated with arsenic, in which Shewanella sp. O23S is the main driving agent.

Physiological and Metagenomic Analyses of Microbial Mats Involved in Self-Purification of Mine Waters Contaminated with Heavy Metals

“…ZS mine communities were already examined using low-throughput methods, including culturing of arsenic-transforming bacteria (Drewniak et al, 2008 , 2010 , 2015 ) or 16S rRNA amplification (Drewniak et al, 2012 ; Tomczyk-Zak et al, 2013 ), indicating their high potential for heavy metals utilization. However, they were never analyzed more deeply using novel techniques applying metagenomic sequencing.…”

Genomic Analysis of Shewanella sp. O23S—The Natural Host of the pSheB Plasmid Carrying Genes for Arsenic Resistance and Dissimilatory Reduction

“…O23A was the first described DARB strain belonging to this genus, showing also interesting properties of iron–arsenic mineral dissolution, both directly and indirectly—due to siderophore production, but also potential for increased adherence factor and biofilm production, which in turn may play a role in entrapment (immobilization) of arsenic and other heavy metal ions within its structure [4]. As it has been previously shown by Drewniak et al [10], Shewanella sp. O23S shares these properties, being capable to directly and indirectly mobilize arsenic from rocks and minerals.…”

Reduction of alternative electron acceptors drives biofilm formation in Shewanella algae

“…The anaerobic reduction pathways of Shewanella spp. have been shown to be promiscuous, sometimes involving the simultaneous utilization of several electron acceptors 56 . Oxygen limitation has been shown to elicit swift changes in energy metabolism, cytochrome production, and formation of conductive nanowires in S. oneidensis MR-1 57 .…”