Enhanced phenol degradation and responses of suspended/attached microbial communities in alternating current bioelectrochemical reactor

The effects of alternating current (AC) stimulation on phenol biodegradation and the response of microbial communities with distinct morphologies remain unclear. In batch test, the maximum ratio of biodegradation rate constant value was about 7.38±1.35-fold for 10 Hz 0.4 V, at a phenol concentration of 800 mg/L, and the biomass of suspended microbes at 10 Hz 0.4 V condition increased by an average of 31.79%, the abundance of Rhodanobacter , Leifsonia were enriched. In continuous test, the optimal condition for AC stimulation was 10 Hz 0.4 V, and compared with non-electrified group, the average removal of phenol increased by 32.52% at a phenol influent concentration of 1000 mg/L, and the biomass increased by 111.07%. Special microbes related with genera of Rhodobacter, Comamonas were distinctively enriched. According to the metagenomic sequencing, the expression of DNA-guided RNA polymerase , RNA helicase , and DNA helicase were incremental with the proper AC stimulation, which positively correlated with phenol biodegradation rate. This study provides new insight into the enhanced aerobic biodegradation of phenol using AC stimulation. • AC stimulation enhanced aerobic phenol biodegradation rate • Different current frequencies caused changes in aerobic suspended and attached microbial biomass. • Functional microbes were enriched for degrading phenol under AC stimulation. • AC stimulation enriched genes encoding key enzymes for phenol metabolism.