多氯联苯降解菌的筛选、鉴定及其降解特性研究

Isolation,Identification and Characterization of a PCBs-degrading Bacterium

以联苯为唯一碳源和能源从河海交汇处筛选、分离得到一株多氯联苯降解菌,研究其多氯联苯降解特性。以联苯(BPH)和4-一氯联苯(PCB3)为底物,探究假单胞菌属(Pseudomonas sp.)P-6-5的生长情况及降解能力。降解菌最适生长pH为7,盐度为35 g/L。以BPH和PCB3为诱导剂,均能促进降解菌的生长。P-6-5对10-100 mg/L的PCB3存在不同程度的转化能力,对浓度为10 mg/L的PCB3降解率达95.3%,最大降解速率1.9 mg/(L·h)。P-6-5对mix13(13种多氯联苯的同系物)中的四氯及四氯以下多氯联苯均有降解能力。结合产物分析,推测降解菌可能具有矿化PCB3的能力。菌株P-6-5具有海水菌的特点,表现了宽广的底物利用范围,是一株高效PCBs降解菌,对环境中PCBs的生物修复具有重要意义。

This study is aimed to investigate the degradation characteristics of PCBs-degrading strain screened and isolated from estuary utilizing biphenyl as sole carbon and energy source. Pseudomonas sp. P-6-5 was investigated in more details of growth and substrate utilization pattern towards BPH and PCB3. The optimal growth conditions for strain P-6-5 were pH 7.0 and salinity 35 g/L. The use of BPH and PCB3 as an inducing agent promoted the growth of degrading bacteria. Strain P-6-5 had the transformation ability to PCB3 with substrate concentration of 10-100 mg/L. The degradation rate of PCB3 by strain P-6-5 was 95.3% in cultures containing 10 mg/L PCB3 and the maximum degradation speed was 1.9 mg/L·h. The PCBs substrate spectrum was assessed by mix13（a mixture of 13 PCB congeners）and the data showed that P-6-5 had the ability to degrade up to four chlorinated polychlorinated biphenyls. Combined with product analysis,we speculated that strain P-6-5 may have the ability to mineralize PCB3. In conclusion,Pseudomonas sp. P-6-5 has the characteristics of seawater bacteria and shows a broad range of substrate spectrum. These results postulate that the P-6-5 is an efficient PCBs-degrading strain,and has a great potential to be utilized in the bioremediation of PCBs pollution.