Diversity of methanol and chloromethane-utilizing microorganisms in an European beech soil identified by DNA SIP

The ozone-destroying volatile organic compound chloromethane (CH3Cl) is naturally produced in tree vegetated ecosystems, and represents a potential growth substrate for specialized methylotrophic microorganisms. Methanol (CH3OH), another C1 growth substrate of methylotrophs, is produced in much larger amounts in the same environments. In this study, bacterial CH3Cl utilization in and the effect of CH3OH as a methylotrophic co-substrate in CH3Cl utilization were investigated. To identify metabolically active key players in this CH3Cl sink, taxonomic (16S rRNA) and functional gene markers (cmuA, mxaF_xoxF, mch) were employed in combination with a stable isotope labeling experiment in topsoil samples of a German forest soil amended with CH3Cl and CH3OH, added alone or together as the [13C]-labeled form, or as the regular, [12C]-unlabeled form of the compound.