Identification and Phylogenetic Analysis of New Sulfate-Reducing Bacteria Isolated from Oilfield Samples

Abstract

Microbiologically infl uenced corrosion (MIC) caused by sulfate-reducing bacteria (SRB) has been investigated in an oilfi eld injection water system. Strain CW-01 was isolated from an oilfi eld and strain CW-04 was isolated from biofi lm dirt of pipeline walls. The strains were facultative anaerobes, non-motile, Gram-positive, pole fl agellum, and spore-forming curved rods. The growth was observed over the temperature range 20-70 ºC. Strain CW-01 grew optimally at 37 ºC. The pH range for growth was 3.0-11, optimal at pH 6.0. Strain CW-04 grew optimally at 48 ºC. The pH range for growth was 3.0-10, optimal at pH 7.2. The strains grew at a very broad range of salt concentrations. Optimal growth was observed with 1.5 g/L NaCl for strain CW-01 and 0.7 g/L NaCl for strain CW-04. The strains showed most similarity in physiological characteristics, except for acetone and saccharose. Analysis of the 16S rDNA sequences allowed strains CW-01 and CW-04 to be classifi ed into the genus Desulfotomaculum. The corrosion speciality of the strains had been comparatively investigated. Especially SRB's growth curve, bearable oxygen capability, drug fastness and corrosion rate had been analyzed. The results showed that it is diffi cult to prevent bacterial corrosion caused by these two strains.