盐池采油区污染土壤石油降解菌的筛选鉴定及其降解特性

Screening,Identification and Characteristics of Petroleum Degrading Bacteria from the Contaminated Soil of Yanchi Aera

从宁夏盐池原油污染土壤中分离筛选高效石油降解菌,研究菌株的降解特性及其对污染土壤的修复效果,以期为该地区石油污染土壤的微生物修复提供高效菌源和理论依据。通过富集培养和分离纯化的方法筛选石油降解菌,结合菌株生理生化特征和16S rRNA基因序列对其进行鉴定;根据菌株产表面活性剂的能力和原油降解率,筛选2株高效菌株制备单一菌剂和复合菌剂,研究其对石油污染土壤的修复作用。结果表明,共分离出石油降解菌25株,多为革兰氏阳性细菌,隶属于12个属,其中链霉菌属和假单胞菌属各6株,为优势菌,红球菌属3株,芽孢杆菌属2株,其他8属各有1株,多样性丰富。菌株具备不同的产表面活性剂能力和原油降解率,其中红球菌属菌株S25和S18原油降解率最高,分别为50.0%和47.2%,Cytobacillus属S19和链霉菌属S10次之,降解率均为44.4%,假单胞菌S23最低,仅为25.0%;土壤修复实验表明,以S18和S25制备的单一菌剂孵育污染土壤90 d后,石油降解率分别为62.7%和75.4%,而二者制备的复合菌剂降解效果要显著优于单一菌剂,降解率达到84.7%,表明菌株之间存在协同促进作用,具有开发为土壤修复剂的潜能。

Highly efficient petroleum degrading bacteria were isolated and screened from the crude oil contaminated soil in Yanchi,Ningxia.The degradation characteristics of the strains and their remediation effect on the contaminated soil were studied,aiming to provide efficient microbial resource and theoretical basis for microbial remediation of oil contaminated soil in this area.The petroleum degrading bacteria were screened by the methods of enrichment culture and isolation and purification.The strains were identified based on physiological and biochemical characteristics and the 16S rRNA gene sequence analysis.According to the ability of producing surfactant and the degradation rate of crude oil,two efficient strains were selected to prepare single microbial agent and compound microbial agent,and their remediation effects on petroleum contaminated soil was studied.The results showed that 25 strains of petroleum degrading bacteria were isolated from petroleum contaminated soil,and most of them were gram positive.The strains belonged to 12 genera,including 6 strains each of Streptomyces and Pseudomonas as dominant genus,3 strains of Rhodococcus and 2 strains of Bacillus,and 1 strain each of the other 8 genera,with rich diversity.The strains showed different surfactant producing abilities and crude oil degradation rates.Among them,Rhodococcus strains S25 and S18 presented the highest degradation rates,50.0%and 47.2%,respectively;followed by Cytobacillus S19 and Streptomyces S10 with 44.4%degradation rate.The degradation rate of petroleum by Pseudomonas S23 was the lowest,only 25.0%.Soil remediation experiments demonstrated that the degradation rate of petroleum was 62.7%and 75.4%with the single bacterial agent prepared by S18 and S25 incubated in the contaminated soil for 90 d.The degradation effect of the composite bacterial agent prepared by the two strains was significantly better than that of the single bacterial agent,and the degradation rate reached 84.7%,indicating that there was a synergistic promotion effect between them,and they have the potential to be developed as soil remediation agents.