嗜热硫酸盐还原菌生长特征及其对碳钢腐蚀的影响

采用API-RP38推荐的培养基，从渤海油田分离出嗜热硫酸盐还原菌（SRB）, 对其进行了初步鉴定，并研究了该菌种的生长特征。用电化学手段研究了该嗜热菌种在高温条件下对碳钢腐蚀的影响。结果表明，嗜热SRB生长周期短于常温SRB的生长周期。细菌能在40℃~80℃范围内生长，最佳生长温度为60℃。最佳生长pH范围为6.0~7.6，最适宜pH在7.0左右。 60℃静态挂片实验表明，该嗜热菌对碳钢腐蚀较严重，是空白培养基中的2.6倍。碳钢表面生成不均匀的生物膜，能谱仪（EDS）分析表明，在生物膜不均匀区域腐蚀产物中FeS_x化合物结构不同。 SRB生长过程中电极自腐蚀电位先正移再负移，电化学阻抗谱（EIS）研究表明生物膜的结构随SRB生长而发生变化，从而导致基体材料发生高温微生物腐蚀。

GROWTH CHARACTERISTICS oF THERMoPHILE SULFATE-REDUCING BACTERIA AND ITS EFFECT ON CARBON STEEL

The API-RP38 medium was used to culture the thermophile sulfate-reducing bacteria (SRB) isolated from Bohai oilfield，and the bacteria was preliminarily identified according to its growth characteristics. Additionally, electrochemical means were taken to study the effect of the bacteria on carbon steel. The results show that the growth cycle of the bacteria is shorter than that cultured under normal temperature. The optimum growth temperature of the bacteria is at 60℃ within the growth temperature range from 40℃ to 80℃. The growth pH ranges from 6.0 to 7.6, and the optimum is about 7.0. The mass loss measurement at 60 ℃ in the culture medium indicates that the corrosion on carbon steel in thermophile SRB solution is 2.6 times more serious than that in the blank medium. As an uneven biofilm occurs on the carbon steel surface，energy dispersive spectrometer (EDS) analysis indicates that the corrosion products have various FeS_x structures in the uneven biofilm. The free corrosion potential increases in the first few days, and later decreases. The electrochemical impedance spectroscopy (EIS) shows that the structure changes in accordance with the growth of the bacteria. Therefore, high temperature microbial corrosion occurs on the matrix materials.