Anaerobic Microbial Metabolism of Dichloroacetate
Gao Chen, Nannan Jiang, Manuel I. Villalobos Solis, Fadime Kara Murdoch, Robert W. Murdoch, Yongchao Xie, Cynthia M. Swift, Robert L. Hettich, Frank E. Löffler
Abstract
Dichloroacetate (DCA) is ubiquitous in the environment due to natural formation via biological and abiotic chlorination processes and the turnover of chlorinated organic materials (e.g., humic substances). Additional sources include DCA usage as a chemical feedstock and cancer drug and its unintentional formation during drinking water disinfection by chlorination. Despite the ubiquitous presence of DCA, its fate under anoxic conditions has remained obscure. We discovered an anaerobic bacterium capable of metabolizing DCA, identified the enzyme responsible for DCA dehalogenation, and elucidated a novel DCA fermentation pathway. The findings have implications for the turnover of DCA and the carbon and electron flow in electron acceptor-depleted environments and the human gastrointestinal tract.