Cathode potential regulates the microbiome assembly and function in electrostimulated bio- dechlorination system.

Mechanism of microbiome assembly and function driven by cathode potential in electro-stimulated microbial reductive dechlorination system remain poorly understood. Here, core microbiome structure, interaction, function and assembly regulating by cathode potential were investigated in a 2,4,6-trichlorophenol bio-dechlorination system. The highest dechlorination rate (24.30 μM/d) was observed under − 0.36 V with phenol as a major end metabolite, while, lower (−0.56 V) or higher (0.04 V or −0.16 V) potentials resulted in 1.3–3.8 times decreased of dechlorination kinetic constant. The lower the cathode potential, the higher the generated CH 4 , revealing cathode participated in hydrogenotrophic methanogenesis. Taxonomic and functional structure of core microbiome significantly shifted within groups of − 0.36 V and − 0.56 V, with dechlorinators (Desulfitobacterium , Dehalobacter), fermenters (norank_f_Propionibacteriaceae , Dysgonomonas) and methanogen (Methanosarcina) highly enriched, and the more positive interactions between functional genera were found. The lowest number of nodes and links and the highest positive correlations were observed among constructed sub-networks classified by function, revealing simplified and strengthened cooperation of functional genera driven by group of − 0.36 V. Cathode potential plays one important driver controlling core microbiome assembly, and the low potentials drove the assembly of major dechlorinating, methanogenic and electro-active genera to be more deterministic, while, the major fermenting genera were mostly governed by stochastic processes. [Display omitted] • Cathode potential regulation lead to the differed dechlorination performance. • Low potential stimulated cathode participated hydrogenotrophic methanogenesis. • Microbiome structure shifted and more positive interactions under low potential. • Simplified and strengthened microbial cooperation by cathode potential assembly. • Group of − 0.36 V drove assembly of major functional genera more deterministic. [ABSTRACT FROM AUTHOR]