Construction of a synthetic anaerobic dechlorination microbiome to degrade chlorinated ethenes by application of metabolic interactions principle

Bioaugmentation is a bioremediation approach to treat groundwater contaminated with chlorinated ethenes, but currently it faces challenges such as poor microbiome stability and effectiveness, due to blind species integration and metabolic inhibition. The objective of this study was to create a controllable and functionally stable microbial community for dichlorination application. For this, we utilized targeted screening to identify dechlorinating bacteria from contaminated groundwater, that in combination would form an anaerobic dechlorination microbial community with stabilizing metabolic interactions between the constituents. The results showed that two organohalide-respiring bacterial (OHRB) species were isolated, and these were identified as Enterobacter bugandensis X4 and Enterobacter sichuanensis C4. Upon co-cultivation with lactic acid as the carbon source, the strains demonstrated metabolic interactions and synergistic dehalogenation ability towards trichloroethene (TCE). It was further demonstrated that the functional microbiome constructed with the strains was stable over time and exhibited a robust TCE degradation rate of 80.85% at 13.13 mg/L TCE within 10 days. Additionally, the complete conversion of TCE was achieved through microbiome bioaugmentation, this augmented microbiome increased the degradation rate towards 52.55 mg/L TCE by approximately 30% within 6 days. Additionally, bioaugmentation stimulated the growth of indigenous OHRB, such as Dehalobacter and Desulfovibrio. It also promoted a positive succession of the microbial community. These findings offer valuable insights into the microbial remediation of chlorinated ethenes-contaminated groundwater and offers novel ideas for the construction of an artificial functional microbiome.