Desulfonatronobacter acetoxydans sp. nov.,: a first acetate-oxidizing, extremely salt-tolerant alkaliphilic SRB from a hypersaline soda lake

D Y Sorokin,M N Poroshina,N A Chernyh

doi:10.1007/s00792-015-0765-y

Abstract

Recent intensive microbiological investigation of sulfidogenesis in soda lakes did not result in isolation of any pure cultures of sulfate-reducing bacteria (SRB) able to directly oxidize acetate. The sulfate-dependent acetate oxidation at haloalkaline conditions has, so far, been only shown in two syntrophic associations of novel Syntrophobacteraceae members and haloalkaliphilic hydrogenotrophic SRB. In the course of investigation of one of them, obtained from a hypersaline soda lake in South-Western Siberia, a minor component was observed showing a close relation to Desulfonatronobacter acidivorans—a “complete oxidizing” SRB from soda lakes. This organism became dominant in a secondary enrichment with propionate as e-donor and sulfate as e-acceptor. A pure culture, strain APT3, was identified as a novel member of the family Desulfobacteraceae. It is an extremely salt-tolerant alkaliphile, growing with butyrate at salinity up to 4 M total Na+ with a pH optimum at 9.5. It can grow with sulfate as e-acceptor with C3–C9 VFA and also with some alcohols. The most interesting property of strain APT3 is its ability to grow with acetate as e-donor, although not with sulfate, but with sulfite or thiosulfate as e-acceptors. The new isolate is proposed as a new species Desulfonatronobacter acetoxydans.Electronic supplementary materialThe online version of this article (doi:10.1007/s00792-015-0765-y) contains supplementary material, which is available to authorized users.

Highlights

During the last two decades, intensive microbiological and, recently, molecular ecology investigation of naturally occurring saline, alkaline lakes resulted in a wealth of information on functional structure of natronophilic microbial communities
High rates of sulfidogenesis have been detected in anaerobic sediments even in hypersaline soda lakes and the actual presence of sulfate-reducing bacteria (SRB) was confirmed by the analysis of both the key functional genes of the dissimilatory sulfite reductase and, in some cases, by the 16S rRNA gene analysis (Scholten et al 2005; Foti et al 2007, 2008; Mesbah and Wiegel 2012)
Despite that molecular analysis demonstrated a presence of several clusters apparently belonging to the “complete oxidizing” SRB in the family Desulfobacteraceae, so far, only a single haloalkaliphilic SRB, described as Desulfonatronobacter acidivorans, has been found in soda lakes (Sorokin et al 2012a)

Summary

Introduction

During the last two decades, intensive microbiological and, recently, molecular ecology investigation of naturally occurring saline, alkaline (soda) lakes resulted in a wealth of information on functional structure of natronophilic microbial communities (last reviewed by Sorokin et al 2014a). The most interesting property of strain APT3 is its ability to grow with acetate as e-donor, not with sulfate, but with sulfite or thiosulfate as e-acceptors. Keywords Soda lakes · Haloalkaliphilic · Acetate oxidation · Sulfate-reducing bacteria (SRB) · Desulfobacteracea

Results

Conclusion