Abstract

A slightly curved rod strictly anaerobic, thermophilic bacterium, was isolated from Dagang oil field, China. Its fundamental physiology and corrosion characteristic were analysed. The strain BF4 was Gram-positive. The growth occurred at 45-78°C (optimum was 60°C) and pH 4.5-9.5 (optimum was 7). Substrates could be used involving D-glucose, fructose, sucrose, raffinose, mannose, lactose, lactate, and cellobiose. The 16S rRNA gene sequence analysis indicated that the isolate was affiliated to Caloramator (99% similarity to Caloramator australicus RC3^T). In the presence of lactate, iron (III) and sulfate were reduced. When the strain was cultivated in modified Baar’s medium, black precipitation was found. Weight loss method, electrochemical and surface analysis showed the corrosion behavior of the strain. In the presence of the isolate, the corrosion rate was higher compared to the abiotic control. The results of physiological characteristics and bio-corrosion implicated that the strain BF4 is a special SRB. It might play an important role in the corrosion of equipments of the Dagang oil field.

Key words: Bio-corrosion behavior, thermophilic bacterium, sulfate reduce, hydrogen sulfide.