Dichloromethane (DCM; CH₂Cl₂) is a toxic groundwater pollutant that also has a detrimental effect on atmospheric ozone levels. As a dense non-aqueous phase liquid, DCM migrates vertically through groundwater to low redox zones, yet information on anaerobic microbial DCM transformation remains scarce due to a lack of cultured organisms. We report here the characterisation of DCMF, the dominant organism in an anaerobic enrichment culture (DFE) capable of fermenting DCM to the environmentally benign product acetate. Stable carbon isotope experiments demonstrated that the organism assimilated carbon from DCM and bicarbonate via the Wood–Ljungdahl pathway. DCMF is the first anaerobic DCM-degrading population also shown to metabolise non-chlorinated substrates. It appears to be a methylotroph utilising the Wood–Ljungdahl pathway for metabolism of methyl groups from methanol, choline, and glycine betaine. The flux of these substrates from subsurface environments may either directly (DCM, methanol) or indirectly (choline, glycine betaine) affect the climate. Community profiling and cultivation of cohabiting taxa in culture DFE without DCMF suggest that DCMF is the sole organism in this culture responsible for substrate metabolism, while the cohabitants persist via necromass recycling. Genomic and physiological evidence support placement of DCMF in a novel genus within the Peptococcaceae family, ‘Candidatus Formimonas warabiya’.

二氯甲烷（DCM；CH ₂ Cl ₂）是一种有毒的地下水污染物，也会对大气臭氧水平产生有害影响。作为一种致密的非水相液体，DCM 通过地下水垂直迁移到低氧化还原区，但由于缺乏培养生物，有关厌氧微生物 DCM 转化的信息仍然很少。我们在此报告了 DCMF 的表征，DCMF 是厌氧富集培养物 (DFE) 中的优势生物体，能够将 DCM 发酵为环境友好的产品乙酸盐。稳定碳同位素实验表明，生物体通过 Wood-Ljungdahl 途径吸收 DCM 和碳酸氢盐中的碳。DCMF 是第一个厌氧 DCM 降解群体，也被证明可以代谢非氯化底物。它似乎是一种甲基营养菌，利用 Wood-Ljungdahl 途径代谢来自甲醇、胆碱和甘氨酸甜菜碱的甲基。来自地下环境的这些底物的通量可能直接（DCM、甲醇）或间接（胆碱、甘氨酸甜菜碱）影响气候。在没有 DCMF 的培养物 DFE 中对共生类群的群落分析和培养表明，DCMF 是该培养物中负责底物代谢的唯一生物体，而共生体则通过坏死物循环而持续存在。基因组和生理学证据支持将 DCMF 置于消化球菌科的一个新属“ Candidatus Formimonas warabiya”中。