Vitamin-C-enabled reduced graphene oxide chemistry for tuning biofilm phenotypes of methylotrophs on nickel electrodes in microbial fuel cells

Author: Jamil Islam, Department of Civil and Environmental Engineering

Mentor: Dr. Venkata Gadhamshetty, Department of Civil and Environmental Engineering

Robust biofilms of methylotrophs can enable a biorefinery solely driven by typically discarded greenhouse gases. They can directly generate electric power from gaseous methane microbial fuel cells (MFCs). Considering the unique physiological requirements of methylotrophs, growing their biofilms under anaerobic conditions in MFCs is a challenging task. The current study explores use of reduced graphene oxide (rGO) for tuning surface properties of 3D porous nickel (NF) electrodes that favor the growth of methylotrophic biofilms. We establish that the rGO chemistry enables the development of superhydrophilic, porous 3D rGO/NF electrodes that yields thicker and electroactive biofilms of Gram-negative Rhodobacter sphaeroides. Tests based on electrochemical impedance spectroscopy, cyclic voltammetry and microscopy revealed that the rGO/NF electrodes enhance initial bacterial colonization, biofilm formation and yield ~ 220-fold higher power density compared to the control. These findings can pave a path for realizing the large-scale bioconversion of methane and methane products into electricity.