The parallel electron transfer pathways of biofilm and self-secreted electron shuttles in gram-positive strain Rhodococcus pyridinivorans HR-1 inoculated microbial fuel cell.

Abstract

Microbial fuel cell (MFC) exhibits huge potentials in disposing wastewater and extra energy consumption. Exploring useful microorganisms for MFC is the crucial section. Herein, the electrochemical mechanism of extracellular anaerobic respiration in MFC inoculated with gram-positive Rhodococcus pyridinivorans HR-1, was first revealed. The MFC exhibited rapid recovery of currents on anode, and could recover to maximum output within one hour, with redox peaks near -0.38 and -0.18 V through electron transfer between the biofilm and anode. When the biofilm-based pathway was blocked by wrapping the anode with Millipore filter membrane, HR-1 inoculated MFC could still generate electricity within a longer recovery period (∼35 h) during anolyte exchange. This was proposed as a self-secreted electron shuttle pathway for electron transfer in R. pyridinivorans HR-1. Cyclic voltammetry analysis revealed that the biofilm-based and self-secreted electron shuttle-based pathways co-existed in R. pyridinivorans HR-1 inoculated MFC, which could play synergistic roles in electricity generation.

Key findings

• ▸Biofilm-based pathway for electron transfer between biofilm and anode with redox peaks near -0.38 and -0.18V.
• ▸Self-secreted electron shuttle pathway for electron transfer in R. pyridinivorans HR-1 with longer recovery period.
• ▸Co-existence of biofilm-based and self-secreted electron shuttle-based pathways in R. pyridinivorans HR-1 inoculated MFC.

Keywords

Identifiers

DOI

10.1016/j.biortech.2022.128514

PubMed

36538956

Journal

Bioresource technology

Year

2022