摘要
从陕北长庆油田含菌采气污水中分离出一株硫酸盐还原菌（SRB），革兰氏染色阴性，芽孢染色阴性，表面不光滑，有鞭毛，作摇摆式运动；菌体呈杆状或弧状，尺寸为(0.6~0.8) mm×(1.0~5.0) mm，在SRB测试瓶中呈阳性反应，确定该菌株属于脱硫弧菌属（Desulfovibrio）。液体在无外加Fe2+条件下培养2 d后的菌数约9.5×108个/mL。在适宜条件下分离得到的SRB液体培养6 h后进入对数生长期，48 h达到生长最高峰，稳定约4 h后进入衰亡期。通过电化学阻抗谱和动电位扫描极化曲线法研究了20R钢电极在SRB菌液中的腐蚀行为。结果表明，腐蚀速率随SRB初始浓度的增加而增大，但不呈线性增长，20R钢在SRB原液、稀释10倍、稀释100倍、对照培养基中浸泡3 d的腐蚀速率分别为0.0922、0.0343、0.0284、0.0281 mm/a；在稀释100倍SRB菌液中浸泡7 d的腐蚀速率为0.0578 mm/a，随着浸泡时间的增加，腐蚀速率增大，且其对阴极的促进作用大于阳极。
Abstract
A strain of sulfate reducing bacteria (SRB) was isolated from waste water in Changqing gas filed. The cell of strain was found to be Gram-negative, non-spore-forming, rough, and motile by a flagellum. The cell was rod or arc with 0.6—0.8 μm wide and 1.0—5.0 μm long. The strain showed positive reaction in the SRB test bottle. According to the modality and physiology, it was concluded that the strain belonged to Desulfovibrio sp. The quantity of SRB was 9.5×108 per milliliter after the strain was cultured in liquid for two days without Fe2+. The strain reached logarithmic phase after inoculation for 6 hrs, and reached a peak after 48 hrs, then stabilized about 4 hrs, finally entered a period of decline. The corrosion behaviors of 20R steel in SRB solution were studied by electrochemical impedance spectrometry and polarization curve. The results showed that the corrosion rate increased with increasing initial concentration of SRB, but the relationship was not linear. The corrosion rate of 20R steel soaked in SRB solution, 10 times diluent, 100 times diluent and contrast medium for three days was 0.0922, 0.0343, 0.0284 and 0.0281 mm/a, respectively. The corrosion rate of 20R steel soaked in 100 times diluted SRB solution for seven days was 0.0578 mm/a. The corrosion rate increased with increasing immersion time. The promoting role of SRB on cathode was greater than that on anode.
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