高分子量多环芳烃降解菌筛选及在土壤电动-生物修复中应用

采用富集培养和多环芳烃双加氧酶基因检测方法,从焦化场地多环芳烃污染土壤分离筛选出9株PAHs降解菌。以高分子量多环芳烃芘为唯一碳源进行摇瓶降解实验,结果表明,J6、S5、S4、S2和B4对芘具有较好的降解能力,21 d时芘降解率均达55%以上,其中B4处理芘的降解率最高,达到70.2%。进一步研究了该5株菌及其混合菌对土壤中芘的降解效果,发现混合菌的降解效果高于单菌的降解效果,其中混合菌H4和单菌B4的降解效果较好,49 d时混合菌H4和单菌B4处理土壤中芘的降解率达29.3%和18.3%。经过16S rRNA基因序列比对,鉴定J6菌株为赤红球菌(Rhodococcus ruber),S5为芽孢杆菌属(Bacillus sp.),S4和S2是鞘脂单胞菌属(Sphingopyxis sp.),B4为假单胞菌属(Pseudomonas sp.)。在电场条件下,混合菌H4和单菌B4处理微生物数量及活性均显著提高,芘的降解率较单独H4和B4处理提高33.0%和20.1%,说明筛选出的5株高分子量多环芳烃降解菌具有较强的电场适应能力,可在高分子量多环芳烃污染土壤电动-微生物修复中应用。

Isolation of high molecular weight PAHs degrading bacteria and its application in the electro-bioremediation of contaminated soil

Nine high molecular weight(HMW)-PAH-degrading bacteria were isolated from PAH-contaminated soil of a coking plant site using the enrichment procedure and detection of polycyclic aromatic hydrocarbon dioxygenase gene. The degradation ability of HMW-PAHs was examined in flasks with pyrene as carbon source. The results showed that strains J6,S5,S4,S2 and B4 had stronger degradation ability for pyrene. After 21 days,the degradation rates of pyrene in all treatments were higher than 55%. The degradation rate of pyrene in B4 treatment was the highest,reaching 70. 2%. We further analyzed the degradation ability of five strains and their mixture in pyrene-contaminated soil. Results showed that the degradation rate of pyrene in the treatment inoculating mixed bacteria were higher than that inoculating single bacterium. Among them,the treatments H4(mixture) and B4 had better degradation rate of pyrene,and the degradation rates of pyrene reached 29.3% and 18.3% after 49 d,respectively. J6,S5,S4,S2 and B4 were identified as Rhodococcus ruber,Bacillus sp.,Sphingopyxis sp.,Sphingopyxis sp. and Pseudomonas sp. respectively based on sequence analysis of 16 S rRNA. The abundance and activity of microorganisms in the H4 and B4 treatments under electric field conditions were significantly increased,and the degradation rates of pyrene were 32.9% and 20.1% higher than those with-out electric field conditions. This indicated that five strains of HMW-PAH degrading bacteria had strong electric field adaptability and could be applied in the electro-bioremediation of HMWPAHs contaminated soil.