一株石油降解菌Lysinibacillus fusiformis 23-1的筛选鉴定及原油降解特性

石油泄露造成了严重的环境问题和重大经济损失,微生物修复是解决石油污染的最为有效的途径。从青藏高原石油污染土样筛选产生物表面活性剂的低温石油降解菌,并研究了该菌株对石油的乳化性能、降解特性、降解条件以及对不同碳链烃类的利用。本实验用血平板法分离到一株产表面活性剂石油降解菌23-1,形态学和16S rRNA基因序列分析鉴定其为纺锤形赖氨酸芽孢杆菌(Lysinibacillus fusiformis 23-1),比色法测定该菌株的乳化性能为19.6%,超声波法测定乳化稳定性为37.5%,表明其能够降低油水界面张力,具有增溶作用。质量法测定L. fusiformis 23-1对石油的降解率为57%,适宜降解条件为:初始pH为7.5,温度为25 ℃,培养8 d后获得最佳降解效果。GC-MS方法测定该菌株的石油降解特性,结果表明,该菌对石油中不同碳链的烃类降解能力不同。L. fusiformis 23-1能产表面活性剂,具有较强的降解石油能力,可用于石油污染修复。

Screening,identification and characteristics of Lysinibacillus fusiformis 23-1 for petroleum degradation

Petroleum spill has caused serious environmental problems and enormous economic losses. The microbial bioremediation have been shown to be the most effective way for the removal of petroleum pollution in environments. We isolated a biosurfactant producing and petroleum degrading bacteria from petroleum contaminated soil in the region of Qilian Mountain Baoping River in the Qinghai-Tibet Plateau. We further investigated the petroleum emulsifiability, degradation properties, and degradation conditions of the isolated strain, as well as the uses of hydrocarbons with different carbon chain by the isolated strain. A biosurfactant producing and petroleum degrading strain, assigned as 23-1, was successfully isolated on the medium with petroleum as sole carbon source using the blood plate screening method. Morphological and 16S rRNA gene sequence analysis identified this isolated strain as Lysinibacillus fusiformis strain 23-1. The colorimetric and ultrasonic analysis indicated that the emulsifiability and emulsion stability of strain 23-1 were 19.6% and 37.5%, respectively, suggesting that L. fusiformis strain 23-1 can reduce the oil-water interfacial tension and enhance the oil solubilization. The gravimetric method analysis showed that 57% petroleum added in the medium could be degraded by L. fusiformis 23-1after 8-d incubation, with pH 7.5 and 25 ℃. Further GC-MS measurement indicated that L. fusiformis 23-1 strongly degraded direct chain saturated alkanes, partly degraded the short chain alkanes and long chain alkanes, but weakly degraded the aromatic hydrocarbons. L. fusiformis 23-1 can produce certain biosurfactant and degrade petroleum during growth in the medium added with petroleum as sole carbon source. This strain could be used for bioremediation of petroleum contaminated environments.