耐热石油降解混合菌群的降解性能研究

Study on Degrading Performance of A Thermophilic Oil-Degrading Bacterial Group

针对极端环境下石油污染土壤的生物修复,从克拉玛依油田石油污染土壤中筛选获得一组最适生长温度为45～55℃、最高耐受温度为75℃的耐热石油降解混合菌群KLO-8,该混合菌群由4株单菌组成,16SrDNA序列分析鉴定表明,其中3株为芽孢杆菌(Bacillus sp.)、1株为地芽孢杆菌(Geobacillus sp.)。考察了KLO-8的降解性能,结果表明:最佳培养时间为7d;最佳氮磷比为3∶1;初始pH值偏碱性更利于原油的降解,最佳初始pH值为8;原油浓度不高于10g.L-1时降解效果较好;添加表面活性剂(十二烷基苯磺酸钠)能够提高混合菌群的降油效果,最佳添加浓度为50mg.L-1。气相色谱-模拟蒸馏分析结果表明,KLO-8对C11～C37的正构烷烃降解效果显著,随着碳原子数的增加,混合菌群对原油中正构烷烃的利用率逐渐降低。

For bioremediation of oil-contaminated soil under extreme conditions,a thermophilic oil-degrading bacterial group KLO-8 composed of four single strains was isolated from Karamay Oilfield oil-contaminated soil. Its optimal growth temperature was 45-55 °C, and its highest resistant temperature was 75 °C. Based on 16S rDNA sequence analysis,three single strains of KLO-8 was Bacillus sp. ,one strain was Geobacillus sp.. The degrading performance of KLO-8 were discussed. The results showed that the optimal culture time was 7 d,the optimal nitrogen-phosphorus ratio was 3 ： 1 ,the initial pH value leaning alkalinity was more propitious to crude oil degradation and the optimal initial pH value was 8, the crude oil concentration below 10 g ~ L-1 was suitable,the addition of surfactant （sodium dodecyl benzene sulfonate） was able to improve the crude oil degradation rate and the optimal concentration was 50 mg · L-1. Gas chromatogram-simulation distillation analysis result showed that KLO-8 was able to degrade the n-alkanes ranging from C11 to C37 and the degradation decreased with the long-chain alkanes increasing.