Sulfate-reducing bacteria of the genus Desulfovibrio from south vietnam seacoast

Abstract

Nine strains of sulfate-reducing bacteria were isolated from a biofouling of corroded steel samples incubated in a marine environment near Nha Trang, South Vietnam. Sulfate-reducing bacteria were obtained from all samples with black corrosion products (in rust-filled metal cavities, beneath the Balanus and oyster booths, and beneath Bryozoa or algal colonies). Analysis of the 16S rRNA gene sequences of these strains showed that they belonged to the genus Desulfovibrio, with D. salexigens, D. marinisediminis, D. alaskensis, D. bizertensis D. indonesiensis, and D. dechloracetivorans as the closest phylogenetic relatives (98–99% similarity). According to the 16S rRNA gene sequencing, one Desulfovibrio isolate was related to “D. caledoniensis”, although the similarity did not exceed 97.0%. All strains utilized hydrogen (in the presence of acetate and CO2), lactate, pyruvate, formate, and fumarate, but not acetate. Utilization of other substrates varied from strain to strain. Some isolates were capable of slow autotrophic growth with H2 as the sole electron donor. D. indonesiensis and D. alaskensis strains were tolerant to long-term exposure to atmospheric oxygen exposure and could grow in the presence of 0.1% O2 in the gas phase.