Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318, Leipzig, Germany.
Institute of Soil and Environmental Science, University of Agriculture Faisalabad, Faisalabad, 38000, Pakistan.
Biodegradation. 2018 Aug;29(4):409-418. doi: 10.1007/s10532-018-9838-9. Epub 2018 Jun 18.
The biotransformation of hexachlorocyclohexane isomers (HCH) by two Dehalococcoides mccartyi strains (195 and BTF08) and an enrichment culture was investigated and compared to conversion by the obligate anaerobic strain Clostridium pasteurianum strain DSMZ 525. The D. mccartyi strains preferentially transformed γ-HCH over α-HCH and δ-HCH isomers while β-HCH biotransformation was not significant. In case of the enrichment culture, γ-HCH was preferentially transformed over the δ-HCH, β-HCH and α-HCH isomers. Major observed metabolites in both cases were tetrachlorocyclohexene and as end products monochlorobenzene (MCB) and benzene. Dechlorination of the γ-HCH isomer was linked to an increase in cell numbers for strain 195. γ-HCH transformation was linked to considerable carbon stable isotope fractionation with the enrichment factor ε = - 5.5 ± 0.8‰ for D. mccartyi strain 195, ε = - 3.1 ± 0.4‰ for the enrichment culture and ε = - 4.1 ± 0.6‰ for co-metabolic transformation by C. pasteurianum.
两种脱氯菌 Dehalococcoides mccartyi（195 株和 BTF08）和一个富集培养物对六氯环己烷异构体（HCH）的生物转化进行了研究，并与专性厌氧菌 Clostridium pasteurianum DSMZ 525 菌株的转化进行了比较。D. mccartyi 菌株优先转化 γ-HCH 而不是 α-HCH 和 δ-HCH 异构体，而 β-HCH 的转化则不显著。对于富集培养物，γ-HCH 优先转化为 δ-HCH、β-HCH 和 α-HCH 异构体。在这两种情况下，主要观察到的代谢产物是四氯环己烯，最终产物是单氯苯（MCB）和苯。γ-HCH 异构体的脱氯与 195 株的细胞数量增加有关。γ-HCH 的转化与相当大的碳稳定同位素分馏有关，富集因子 ε 分别为-5.5±0.8‰（D. mccartyi 195 株）、-3.1±0.4‰（富集培养物）和-4.1±0.6‰（C. pasteurianum 共代谢转化）。
