Microbial community and bioelectrochemical activities in MFC for degrading phenol and producing electricity: Microbial consortia could make differences

Abstract

Microbial fuel cell (MFC) and its reactor systems have been intensively investigated for energy production and wastewater treatment using wild bacterial consortia. Yet, there is lack of detailed studies on understanding how multiple wild microorganisms could alter bioelectrochemical reactions in MFC for degrading toxic organic contaminants and generating electricity from industrial wastewater. Hence, this study evaluates the microbial community and bioelectrochemical activities in a lab-scale MFC reactor inoculated by petrochemical industrial microbial consortium (IMC) and domestic microbial consortium (DMC), aiming to enhance MFC performance for degrading 2,4-dichlorophenol (2,4-DCP) and producing electricity. Cutting-edge microbiology analysis techniques were used for identifying microbial community in suspension and biofilm in the IMC and DMC inoculated MFC systems. Research focused on evaluating how the variable microbial population and 2,4-DCP feeding could affect bioelectrochemical activities and MFC performance. Arcobacter, Aeromonas, Pseudomonas, Acinetobacter, Cloacibacterium, and Shewanella sp. in DMC were found to be important bacteria for 2,4-DCP degradation while Bacillus sp. dominated IMC contributing to higher electricity production. This would be the first discovery of Cloacibacterium sp. contributing phenol degradation in MFC. IMC-MFC reactor performed well in producing high 156mA/m2 current density with 41% phenolic degradation, while DMC-MFC showed promising 62% 2,4-DCP reduction and 123mA/m2 current production. MFC systems performed highly comparable 2,4-DCP degradation efficiency than the conventional anaerobic biodegradation. These results demonstrate that wastewater-inoculated MFCs can be capable of simultaneous energy generation and phenolic degradation and provide new insights that may assist with future MFC optimisation.