Diversity and distribution of sulfate-reducing bacteria in four petroleum reservoirs detected by using 16S rRNA and dsrAB genes

Microbial sulfate reduction, an important metabolic process in petroleum reservoirs, is widely known as a major contributor to microbial influenced corrosion and deterioration of oil quality. To better control oil field corrosion and oil degradation caused by the sulfate-reducing bacteria (SRBs), the community structure and composition of SRBs in four oil reservoirs were investigated in this study by comparing clone libraries of 16S rRNA and dissimilatory sulfate reductase (dsrAB) genes. In addition, canonical correspondence analysis (CCA) was also employed to find relationship between biodata and physiochemical information. More information on SRB communities was obtained from nested-PCR-phylogenetic analyses of 16S rRNA genes and PCR primer sets amplifying six groups of SRBs frequently detected in oilfields all over the world were used. Amplified sequences belonging to Desulfotomaculum and Desulfobacter were the most dominant in all four reservoirs. The diversity of SRB communities increased while the temperature of the four oil reservoirs decreased from 63 to 21. Correlations between environmental variables and species distribution indicated that Desulfotomaculum was correlated with temperature, depth, and the concentration of acetate, propionate and sulphate. Desulfomicrobium, Desulfobacter and Desulfobulbus showed positive correlation with sulphur and salinity. Desulfobacterium was influenced by both salinity and the concentration of acetate. The results of this study provided important information on the microbial ecology of sulfate-reducing bacteria in different petroleum reservoirs.