煤炭污染区土壤中苯并(a)芘降解菌的分离鉴定

Isolation and identification of Benzo(a)pyrene-degrading strains in coal-polluted soil

苯并(a)芘是石油、煤炭开采区生态环境中具有代表性的有机污染物,利用新疆煤炭开采区本土微生物资源有效降解苯并(a)芘,对开采区环境治理具有一定的应用价值.采集新疆煤炭开采区受污染土壤,经苯并(a)芘(50 mg/L)为唯一碳源胁迫培养5代,分离筛选出11株降解苯并(a)芘的菌株,通过分子生物学方法确定其分类地位,采用高效液相色谱法(HPLC)检测菌株对苯并(a)芘的降解能力.结果显示:其中8株菌归属为苍白杆菌属(Ochrobactrum sp.),其它3株菌分别为假单胞菌属(Pseudomonas sp.)、污水菌属(Aquamicrobium sp.)和芽孢杆菌属(Geobacillus sp.).获得的11株降解菌以苯并(a)芘为唯一碳源胁迫培养20 d后,降解率可以达到56.1%-82.5%,其中MB-2(Ochrobactrum sp.)和MB-9(Ochrobactrum sp.)对苯并(a)芘的降解率高达82.5%和80.3%.本研究表明,新疆煤矿污染区土壤中蕴含能有效降解苯并(a)芘的微生物,其优势菌种为苍白杆菌属,从而丰富了干旱、寒冷环境中降解有机污染物苯并(a)芘的微生物资源.

Benzo（a）pyrene is a representative organic pollutant in the ecological environments of oil or coal exploration areas. Microbial degradation of benzo（a）pyrene has significant value in environmental management of the coal exploration area in Xinjiang. This study isolated from coal contaminated soil in Xinjiang 11 high efficiency degrading strains through 50 mg/L benzo（a）pyrene stress culture. The strains were identified by the method of molecular biology, and the benzo（a）pyrene degradation ability was tested with high performance liquid chromatography（HPLC）. The results showed that 8 out of the 11 strains belonged to genus Ochrobactrum sp., and each of the other 3 belonged to genus Pseudomonas sp., Aquamicrobium sp. and Geobacillus sp. respectively. After being cultured in benzo（a）pyrene as the sole carbon source for 20 days, their degradation rate was 56.1%–82.5%. Among them, benzo（a）pyrene degradation rate of the sample MB-2（Ochrobactrum sp.） and MB-9（Ochrobactrum sp.） were 82.5% and 80.3%. The result indicated that benzo（a）pyrene degradating strains exist in the coal mine soil in Xinjiang, with Ochrobactrum sp. as the dominant genus. We hope this research can expand the understanding of microbial resources from drought and cold environment for degrading organic pollutants such as benzo（a） pyrene.