鼠李糖脂对微生物菌剂降解石油的影响

以石油烃降解微生物菌剂和铜绿假单胞菌株A6为对象，考察不同浓度鼠李糖脂对菌剂细胞表面疏水性、原油降解性能和微生物生长的影响，采用GC-MS分析石油中正构烷烃组分的降解情况。结果表明，低浓度鼠李糖脂就可提高菌剂细胞的表面疏水性和原油降解效果。以250mg／L添加组最明显，第7天疏水性达最高，为58．6％，比对照组提高约26．2％；降解第15天原油降解率达71．6％，分别比对照组和TW20组提高16％和13．3％。GC-MS结果显示鼠李糖脂对高碳数烷烃的降解作用大于低碳数烷烃，正二十三烷和正三十三烷的降解率分别较对照提高了21．5％和33．7％。菌剂对奇数碳烷烃的降解效果优于偶数碳烷烃。鼠李糖脂分别使菌剂中细菌、放线菌和霉菌的最大生物量提高了5．7、2．4和1．8倍。鼠李糖脂对微生物细胞疏水性和生物量的提高与石油降解效果正相关。

Effects of rhamnolipid on petroleum degradation of compound microbial inoculant

With petroleum-degrading bacterium Pseudomonas aeruginosa A6 and compound microbial inoculant （CMI） as the model, the effects of different concentrations of rhamnolipids on the petroleum-degrading ability, the growth and cell-surface hydrophobicity （CSH） of CMI were investigated. Degradation of N-alkanes was analyzed by GC-MS. The results showed that the CSH and petroleum degradation rates of CMI were enhanced distinctly by rhamno- lipid even at low concentration. 250 mg/L rhamnolipid showed the most obvious effect. The highest CSH was 58.6% in 7 d. Compared with the control group,it increased by 26.2%. Petroleum degradation rate reached 71.6% in 15 d, increased by 16% and 13.3%, respectively compared with that without surfactant and with TW20. GC-MS results showed that the effects of rhamnolipids on higher molecular weight nalkanes were better than lower molecular nal- kanes. The degradation rates of twenty-three alkanes and thirty-three alkanes increased by 21.5% and 33.7% ,respec- tively. The degradation of CMI on odd-numbered carbon nalkanes was better than even-numbered carbon nalkanes. Rhamnolipid could obviously promote the growth of CMI. Compared with the control, the maximum biomass of bacteri- a, actinomycetes and fungi increased 5.7, 2.4 and 1.8 times, respectively. Increased cell surface hydrophobicity andbiomass were beneficial to the degradation of the substrate.