Isolation and identification of a sulfate reducing bacteria and sequence analysis of its dissimilatory sulfite reductase gene

A sulfate reducing bacteria was isolated from mining sewage of Daqing Oilfield by Hungate anaerobic technology. Physiological-biochemical analysis showed that the strain could utilize polyacrylamide as sole carbon and nitrogen source. The sequence analysis of 16S rDNA illustrated that the similarity of F8 and Desulfovibrio desulfuricans(AF192153)was 99%, and the similarity sequence of dissimilatory suifite reductase gene (DSR)cloned from the strain and Desulfovibrio desulfuricans(AF273034)was 98%. Their phylngenitic anal-ysis was basically anastomosed, and thus temporarily named as Desulfovibrio desulfuricans F8. The DSR cloned from F8 strain was 2740 bp in length consisting of three ORF, DSRA, DSRB and DSRD as a single operon (DSRABD)regulated by the same operator. DSRA contained typical conservative box of sulfate--sulfite reduc-ing enzyme(Site Ⅰ and Site Ⅱ), which could bind siroheme andFe_4S_4] . DSRB retained aFe_4S_4] binding site, with an uncomplimentary structure for siroheme binding. There was no conservative box in DSRD. Se-quence analysis of DSR will provide a theoretical basis for quantitative detection, metabolic pathway modification through gene engineering, and sulfate reducing bacteria(SRB)suppression.