A systematic understanding of microbial reductive dechlorination towards an improved "one health" soil bioremediation: A review and perspective

Chlorinated organic pollutants (COPs), both emerging and traditional, are typical persistent pollutants that harm soil health worldwide. Dechlorinators mediated reductive dechlorination is the optimal way to completely remove COPs from anaerobic soil through a redox reaction driven by electron transfer during microbial anaerobic respiration. Generally, the dechlorinated depletion of COPs in situ often interacts with multiple element biogeochemical activities, e.g., methanogenesis, sulfate reduction, iron reduction, and denitrification. Elucidating the relevance of biogeochemical cycles between COPs and multiple elements and the coupled mechanisms involved, thus, helps to develop effective pollution control strategies with the balance between pollution degradation and element cycles in heterogeneous soil, ultimately contributing to "one health" goal. In this review, we summarized the microbial-chemical coupling redox processes and the driving factors, elucidated the interspecies metabolites exchange and electron transfer mechanisms within COP-dechlorinating communities, and further proposed a detailed design, construction, and analysis framework of engineering COP-dechlorinating microbiomes via "top-down" self-assembly and "bottom-up" synthesis to pave the way from laboratory to practical field application. Especially, we delve into the major challenges and perspectives surrounding the design of state-of-the-art synthetic microbial communities. Our goal is to improve the understanding of the microbial-mediated coupling between reductive dechlorination and element biogeochemical cycling, with a particular focus on the implications for health-integrated soil bioremediation under the "one health" concept.