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Enrichment and isolation of acidophilic sulfate‐reducing bacteria from T into R iver sediments
Author(s) -
SánchezAndrea Irene,
Stams Alfons J. M.,
Amils Ricardo,
Sanz José Luis
Publication year - 2013
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12066
Subject(s) - bacteria , firmicutes , 16s ribosomal rna , microbiology and biotechnology , sulfate reducing bacteria , biology , sulfate , biochemistry , chemistry , food science , genetics , organic chemistry
Summary Although some acidophilic and alkaliphilic species have been described recently, most of the known sulfate‐reducing bacteria ( SRB ) grow optimally at neutral pH. In this study, sulfate reduction was studied with sediment samples from the extremely acidic T into R iver basin. Stable enrichments of SRB were obtained at pH 4 with glycerol, methanol and hydrogen; at pH 4.5 with lactate and at pH 5.5 with succinate as substrates. Inhibition of sulfate reduction by organic acids below their p K a was observed. Cloning and sequencing of 16 S r RNA gene showed that fermentative bacteria ( P aludibacter spp., O scillibacter spp.) and SRB ( T hermodesulfobium spp., D esulfosporosinus spp., D esulfitobacterium spp., D esulfotomaculum spp.) were co‐enriched. By repeated serial dilutions and streaking on agar plates, four strains of SRB belonging to the F irmicutes phylum were obtained. Two of them show 96% 16 S r RNA gene sequence similarity with D esulfosporosinus acidophilus, and a third one with D esulfosporosinus orientis . Another isolate has just 93% r RNA gene sequence similarity with the D esulfosporosinus/ D esulfitobacterium cluster and might represent a novel species within a novel genus. One of the D esulfosporosinus strains was further investigated showing maximum growth at pH 5.5, and a pH ‐dependent inhibitory effect of organic acids and sulfide.