[A Thermotolerant and Halotolerant Sulfate-reducing Bacterium in Produced Water from an Offshore High-temperature Oilfield in Bohai Bay, China: Isolation, Phenotypic Characterization, and Inhibition].

The growth and activity of sulfate-reducing prokaryotes (SRP) in oilfield environments could produce large amounts of HS, leading to multifaceted problems, including oilfield souring and microbially-influenced corrosion, yet knowledge about the diversity and physiology of SRP therein was quite limited. To further understand the phenotypic characteristics of SRP residing in an offshore high-temperature oilfield at Bohai Bay, China, and to explore the potential methods for control of SRP-mediated problems, we isolated, using Hungate techniques, a thermotolerant, halotolerant SRP strain, designated BQ, from the produced water of a high-temperature. We also presented the phenotypic features of BQ, and investigated the efficacy of five biocides, or metabolic inhibitors, in suppressing the sulfidogenic activity of BQ. Cells of BQ were motile, short rod-shaped, 1.2-2.5 μm in length and 0.5-0.8 μm in width. Although BQ shared 99% 16S rRNA gene sequence similarity with Hildenborough, distinct phenotypic traits between them were observed. Isolated BQ could grow at 14-70℃(optimum at 30℃) and pH 6.0-9.0 (optimum pH 7.0), and in the presence of 0%-10% NaCl. Isolated BQ utilized a wide range of carbon substrates, including sodium formate, sodium lactate, and acetate. Sulfate, sulfite, thiosulfate, and sulfur were utilized as electron acceptors, but not nitrate or nitrite. Sodium hypochlorite (600 mg·L), Benzyltrimethylammonium chloride (300 mg·L), or nitrate (800 mg·L) failed to inhibit HS production by BQ. By contrast, glutaraldehyde (50 mg·L), bronopol (30 mg·L), chlorine dioxide (50 mg·L), and nitrite (70 mg·L) inhibited HS production by BQ for at least 30 d, indicating that these compounds may be suitable for the mitigation of microbial souring in this specific, high-temperature, offshore oilfield at Bohai Bay, China.