Acetogenic microbial degradation of vinyl chloride

Under methanogenic conditions, microbial degradation of [1,2-C-14]vinyl chloride (VC) resulted in significant (14 +/- 3% maximum recovery) but transient rec every of radioactivity as C-14-acetate. Subsequently, C-14-acetate was degraded to (CH4)-C-14 and (CO2)-C-14 (18 +/- 2% and 54 +/- 3% final recoveries, respectively). In contrast, under 2-bromoethanesulfonic acid (BES) amended conditions, C-14-acetate recovery remained high (27 +/- 1% maximum recovery) throughout the study, no (CH4)-C-14 was produced, and the final recovery of (CO2)-C-14 was only 35 +/- 4%. These results demonstrate that oxidative acetogenesis may be an important mechanism for anaerobic VC biodegradation. Moreover, these results (1) demonstrate that microbial degradation of VC to CH4 and CO2 may involve oxidative acetogenesis followed by acetotrophic methanogenesis and (2) suggest that oxidative acetogenesis may be the initial step in the net oxidation of VC to CO2 reported previously under Fe(III)-reducing, SO4-reducing, and humic acids-reducing conditions.