Long-Term Dechlorination Performance of the Dehalococcoides-Augmented Bioelectrochemical System and the Functional Microorganism Identification

Abstract

Electroactive bacteria in microbial communities contribute to electrode-driven dechlorination by Dehalococcoides (Dhc.). To pre-argument Dhc. to bioelectrochemical system to construct the functional consortia is a promising strategy for achieving the complete dechlorination. However, the stability of the long-term dechlorination performance is poorly understood. And the role of electroactive bacteria during the electron transfer (ET) between Dhc. and the electrode has not been studied in co-culture tests within a bioelectrochemical system. To address this gap, we performed the long-term operation with a Dehalococcoides-augmented bioelectrochemical system and enriched functional microorganisms that contribute to ET from the electrode to Dhc. by constructing a stable bioelectrochemical dechlorination system. Subsequently, we cultivated Desulfosporosinus meridiei (Dm), a predicted functional species, in co-culture with Dhc. when −0.3 V (relative to a standard hydrogen electrode) is applied. Our results showed that Dhc./Dm co-cultures improved the maximum ethylene production rate by approximately fourfold compared with the Dhc. monoculture. In addition, Desulfosporosinus facilitated ET between the electrode and Dhc. by enhancing H2 production. These findings provide a theoretical framework for comprehending how electroactive bacteria contribute to bioelectrochemical dehalogenation.

Keywords: bioelectrochemical, dechlorination, dehalogenation, electroactive, Electron transfer