氯代烯烃胁迫下菌群SWA1的降解活性及群落结构

Biodegrading activity and community structure of microbial consortium SWA1 acclimatized on chloroalkene

以填埋场覆盖土筛选的可高效降解三氯乙烯(TCE)的混合菌群SWA1为研究对象,考察了其对高浓度氯代烯烃的耐受性及微生物群落变化.SWA1对反-1,2-二氯乙烯(t-1,2-DCE),TCE和四氯乙烯(PCE)的最高耐受浓度分别可达580,250,500mg/L,远高于已报道菌株.生物降解研究结果表明SWA1可有效去除氯代烯烃,菌群生长到稳定期,对t-1,2-DCE的去除率高于90%.高通量测序结果和相关性分析显示不同氯代烯烃驯化后SWA1群落结构存在显著性差异,t-1,2-DCE共代谢生物降解中参与甲烷氧化和氯代烃降解的优势菌属分别为Methylophilus(相对丰度为17.4%~26.6%)和Methylomonas(相对丰度为31.7%~62.2%);TCE共代谢降解中参与甲烷氧化和氯代烃降解的优势菌属分别为Methylophilus(相对丰度为26.9%~46.3%)和Methylocystaceae(相对丰度为1.7%~33.4%).群体感应分析表明微生物间互利共生关系促进了SWA1的生物氧化.

In this study,the tolerance of microbial consortium SWA1which was screened from landfill cover soil and good at degrading trichloroethylene(TCE)to chloroalkenes was evaluated.The maximum tolerated concentration of SWA1for t-1,2-dichloroethene(t-1,2-DCE),TCE and tetrachloroethylene(PCE)were580,250and500mg/L,respectively,which was significantly higher than that published.The biodegradation of chloroalkenes by SWA1was further studied.The results showed that chloroalkenes could be efficiently removed by SWA1and over90%of t-1,2-DCE were removed in microbial consortium SWA1at mid-stationary phase.The dynamic composition structure and diversity of SWA1were determined by MiSeq sequencing.The results indicated that there were significant differences in community structure of SWA1acclimatized by different chloroalkenes.Correlation analysis showed that the dominant bacteria Methylophilus with abundance of17.4%~26.6%and Methylomonas with abundance of31.7%~62.2%were closely related methane oxidation and co-metabolic biodegradation of t-1,2-DCE,respectively.Similarly,the dominant bacteria Methylophilus with abundance of26.9%~46.3%and Methylocystaceae with abundance of1.7%~33.4%were responsible for methane oxidation and co-metabolic biodegradation of TCE.Overall,Network analysis revealed that quorum sensing improved the oxidative activity of SWA1.