鼠李糖脂产生菌M7-6在模拟油藏条件下的培养基优化

Optimization of culture medium for rhamnolipid producing bacterial strain M7-6 under simulated oil reservoirs conditions

基于已筛选出的鼠李糖脂产生菌M7-6,在模拟油藏条件(温度、pH、矿化度及缺氧)下,对该菌株的激活剂配方进行了碳源、氮源、碳氮比(C/N)、无机盐等因素的优化,并考察了该菌株在模拟油藏条件下的最佳接种量;利用厌氧发酵罐对菌株M7-6进行了扩大培养,评价菌M7-6的原位代谢活性及与其他微生物类群的竞争作用。结果表明:以甘油为碳源、硝酸盐为氮源、C/N为14.4∶1时,最利于菌株M7-6在模拟油藏条件下生产鼠李糖脂,最小接种量为1%(体积分数)。在厌氧发酵罐中,菌株M7-6可以将培养体系的表面张力降至38.4 mN/m;并且体系中烃降解菌和产酸菌数量有所增加,而硫酸盐还原菌数逐渐减少。

Based on a rhamnolipid producing bacterial strain Pseudomonas aeruginosa M7-6, medium （carbon source,nitrogen source, C/N ratio, and mineral factors） was optimized for efficiently producing rhamnolipid under simulated oil reservoir conditions（temperature, pH and absence of oxygen）.Using the optimized medium,effect of different inoculums amount on anaerobic production of rhamnolipid by M7-6 was studied. Strain M7-6 was cultured in a 6-L anaerobic fermentor using oilfield production water to prepare medium,to evaluate the rhamnolipid production by M7-6 under simulated conditions and study the competitive activity of M7-6 with other native microorganisms. M7-6 could efficiently produce rhamnolipid under simulated conditions with glycerol as carbon source and nitrate as nitrogen source.Theoptimum C/N ratio is 14. 4： 1, and the least inoculums amount is 1 % （ V/V）. Strain M7 -6 can reduce surface tension ol culture system to 38. 4 mN/m in the anaerobic fermenter. Moreover,the numbers ol oil degrading bacteria and acid producing bacteria were increased, and the number of sulfate reducing bacteria was decreased.