大连新港原油降解微生物的分离纯化及降解效率评价

Isolation of oil-degrading bacteria from Dalian New Port and evaluation of their oil-degrading abilities

目的在大连新港原油污染海域分离纯化出可降解原油的"土著"微生物,评价其原油降解能力,并研究提高降解效率的方法。方法取海水样品进行富集培养,分离纯化出"土著"原油降解微生物,以16S rDNA测序法鉴定微生物种类,并采用MEGA 5.0进行多序列比对分析,选用最大相似法构建系统发育树。在实验室纯培养的条件下以气相色谱法对微生物的原油降解能力进行分析,选出优势菌种,再将优势菌种混配分析最佳原油降解条件。结果分离纯化得到的"土著"原油降解微生物分属枯草芽孢杆菌属、动性球菌属、嗜冷菌属等多个菌属,"土著"原油降解微生物资源丰富,优势菌种的混配有助于加快和提高原油降解效率,是有效且对生态环境友好的生物处理法。

Objective To isolate indigenous oil-degrading bacteria from Dalian New Port and evaluate their bioremediation poten- tial, and explore the methods to improve their oil-degrading efficiency. Methods The bacterial strains were isolated by enrichment culti- vation from the crude oil-contaminated water samples, and were identified by partial sequencing of 16S rRNA gene; a phylogenetic tree was constructed using Maximum Likelihood method by MEGA 5.0. The oil-degrading ability of the isolates under pure culture condition was detected by gas chromatography. A bacteria consortium was constructed by mixing 4 isolates with equal proportions. Results The l0 isolated indigenous oil-degradating bacteria were able to utilize crude oil as sole carbon and energy source, with degradation rate ranging from 22.0% to 78.4% after 20-day＇ s cultivation. 16S rDNA sequence analysis showed that these isolates belonged to Bacillus, Planococ- cus, Psychrobacter, et al. A consortium of 4 isolates showed high degradation ability of about 85.4%. Conclusion The natural resources of oil-degrading microorganisms in Dalian New Port area is abundant and with great bioremediation potential. The use of mixed indigenous bacteria would be an effective and eco-friendlv technology for the degradation of crude oil.