Unexpected effects of electrode oxidation in electrochemical polymerization of L-arginine on electrochemically active bacteria in microbial electrochemical system

In-situ electrochemical polymerization of L-arginine (LA) is an efficient way to increase electrode positivity, but may induce electrode oxidation (EO) on carbon cloth surface. So far, the effects of EO on electrochemically active bacteria (EAB) remain unclear. This study first demonstrates the adverse effects of EO on pure-cultured and mixed-cultured EAB. Results demonstrated that PLA was formed in the initial stage of electrochemical polymerization of LA, while EO occurred in the following stage. EO largely increased electrochemical active surface area and conductivity. However, the positive effect of PLA modification on biomass was completely damaged by EO modification. Furthermore, EO inhibited EAB enrichment in microflora. This study provides suggestions for electrode electrochemical modification, and EO should be minimized in the practical application.