School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, Iran.
Colloids Surf B Biointerfaces. 2011 Jun 1;84(2):292-300. doi: 10.1016/j.colsurfb.2011.01.011. Epub 2011 Feb 3.
The biosurfactant production potential of a new microbial consortium of Enterobacter cloacae and Pseudomonas sp. (ERCPPI-2) which was isolated from heavy crude oil-contaminated soil in the south of Iran, has been investigated under extreme environmental conditions. The isolated consortium produces a biosurfactant mixture with excessive oil spreading and emulsification properties. This consortium was able to grow and produce biosurfactant at temperatures up to 70 °C, pressures up to 6000 psia, salinities up to 15% (w/v), and in the pH range 4-10. Besides, the optimum biosurfactant production conditions were found to be 40 °C and 7.0 for the temperature and pH value, respectively. These conditions gave the best biosurfactant production of 1.74 g/1 when the cells were grown on a minimal salt medium containing 1.0% (w/v) olive oil, 1.0% (w/v) sodium nitrate supplemented with 1.39% (w/v) K(2)HPO(4) at 40 °C and 150 rpm after 48 h of incubation. The ERCPPI-2 could reduce surface and interfacial tensions to 31.7 and 0.65 mN/m from the original values of 58.3 and 16.9 mN/m, respectively. The isolated consortium produced biosurfactant using heavy crude oil as the sole source of carbon and emulsified the available heavy crude oil up to E(24)=83.4%. The results of the core holder flooding tests at simulated reservoir conditions demonstrated that the oil recovery efficiency due to the injection of the cell-free biosurfactant solution was 27.2%, and the bacterium injection reduced the final residual oil saturations to below 3% at optimum conditions.
从伊朗南部受重油污染的土壤中分离出的肠杆菌和假单胞菌（ERCPPI-2）新微生物联合体，在极端环境条件下，其生物表面活性剂的产生潜力得到了研究。该联合体产生了一种生物表面活性剂混合物，具有极好的油展和乳化性能。该联合体能够在温度高达 70°C、压力高达 6000 psia、盐度高达 15%（w/v）和 pH 值 4-10 的范围内生长并产生生物表面活性剂。此外，发现最佳生物表面活性剂生产条件为温度 40°C 和 pH 值 7.0。当细胞在含有 1.0%（w/v）橄榄油、1.0%（w/v）硝酸钠的最小盐培养基中生长，并在 40°C 和 150 rpm 下培养 48 小时时，可获得最佳生物表面活性剂产量 1.74 g/L。ERCPPI-2 可以将表面和界面张力从原始值 58.3 和 16.9 mN/m 分别降低到 31.7 和 0.65 mN/m。该联合体使用重油作为唯一的碳源产生生物表面活性剂，并将可用的重油乳化至 E(24)=83.4%。在模拟油藏条件下的岩心夹持器驱替试验结果表明，由于注入无细胞生物表面活性剂溶液，采收率提高了 27.2%，在最佳条件下，细菌注入将最终残余油饱和度降低至 3%以下。
