烃降解菌WJ-1及其生物表面活性剂特性研究

Physicological and Biochemical Characteristics of Hydrocarbon-Degrading Strain WJ-1 and Its Biosurfactants

从蒙古林油田水样筛选得到一株能以烃类为唯一碳源、高产表面活性剂的烃降解菌WJ-1,经16SrDNA初步鉴定为铜绿假单胞菌Pseudomonas aeruginosa。该菌株以大豆油为碳源的培养基发酵7天,发酵液表面张力降到25.586mN/m,排油圈直径增大到11.8cm。薄层色谱分析表明所产表面活性剂主要有鼠李糖脂、蛋白类和脂类,蒽酮法测得96小时发酵液中鼠李糖脂含量最高,为55g/L;从发酵液提取的棕黄色生物表面活性剂(粗品),其表观临界胶束浓度为20mg/L;以不同黏度的4种原油作为碳源培养7天,原油平均降解率为52%。在渗透率0.4μm2的物理模型上,以1PV的0.6%WJ-1菌液、0.6g/L的聚合物溶液、0.6%WJ-1菌液+0.6g/L的聚合物溶液分别驱替水驱残余油,采收率分别提高6.56%、9.08%、23.08%,表明该菌可用于微生物采油。

A hydrocarbon-degrading facultative bacterial strain, WJ-1, able to grow on hydrocarbons as sole carbon source and to produce large amount of biosurfactants, was isolated from the oil reservoir brines of Menggulin oil field, Huabei, and assigned to Pseudomonas aeruginosa on the basis of partial sequencing of 16Sr DNA. The surface tension of the growth medium on bean oil dropped down to 25. 568 mN/m and the radius of oil spreading in it enlarged to 11.5 cm after WJ-1 having been cultivated in this medium over 7 days. TLS analyses showed that the biosurfactants produced by WJ-I were rhamnolipids, proteins, and other lipids. The maximal rhamnolipids yield determined by anthrone method of analysis was of 55 g/L and was observed in the growth medium in 96 hrs of fermentation. The CMC value of the brown-yellow active substances extracted from the fermentation broth was of 20 mg/L. The degradability of 4 crude oils of different viscosity,on which WJ-1 was clutivated in 7 days,was of 52% in average. The residual oil in artificial cores after water flood was drived by 1 PV of 0. 6% broth, 0. 6 g/L polymer solution, and 0. 6% broth ＋ 0. 6 g/L polymer solution and an enhancement in oil recovery of 6. 56%, 9.08%, and 23.08%, respectively, was observed, which revealed promising prospect of this strain in MEOR.