Unveiling the microbial co-metabolism behavior for electrical-driven degradation of phenol in bioanode

Abstract

Uncovering the behavior of microbial co-metabolism will provide a vision of microbial mutualistic mechanisms for degrading refractory organics by bioanode and expedite the application of microbial electrochemical technology. Here, microbial co-metabolism is established by adding acetate sodium and is used to stimulate the electrical-driven degradation (e-degradation) of phenol by bioanode. The efficiency of e-degradation for 50 mg L- 1 phenol achieved 24.8 % and the total electron recovery was improved by 289 f 40 % compared with that without microbial co-metabolism. This improvement is found for the e-degradation of 20 mg L- 1, 30 mg L- 1, and 100 mg L- 1 phenol. A big external resistance would inhibit the metabolism of exoelectrogens and lead to a decrease in electron recovery. Abundant exoelectrogens (Geobacter spp. and Pseudomonas spp.) are enriched in bioanode with microbial co-metabolism and the biofilm can perform extracellular electron transport through various pathways with the mid-potential of -0.24 V and -0.42 V, respectively. In addition, elevated amounts of intermediates for phenol e-degradation further demonstrate that microbial co-metabolism stimulates the conversion of phenol in bioanode. The insights gained from this study will assist in disclosing microbial interaction behavior in degrading refectory pollutants by bioanode.