Influence of inoculum and anode surface properties on the selection of Geobacter -dominated biofilms

Abstract

This study evaluated the impact of inoculum source and anode surface modification (carboxylate -COO(-) and sulfonamide -SO2NH2 groups) on the microbial composition of anode-respiring biofilms. These two factors have not previously been considered in detail. Three different inoculum sources were investigated, a dry aerobic soil, brackish estuarine mud and freshwater sediment. The biofilms were selected using a poised anode (-0.36 V vs Ag/AgCl) and acetate as the electron donor in a three-electrode configuration microbial fuel cell (MFC). Population profiling and cloning showed that all biofilms selected were dominated by Geobacter sp., although their electrochemical properties varied depending on the source inoculum and electrode surface modification. These findings suggest that Geobacter sp. are widespread in soils, even those that do not provide a continuously anaerobic environment, and are better at growing in the MFC conditions than other bacteria.

Reductive electrografting of in situ produced diazopyridinium cations: Tailoring the interface between carbon electrodes and electroactive bacterial films

“…[3],[4], [5], [6], [7], [8] Among these strategies, the chemical functionalization of the bioanode through diazonium chemistry has been demonstrated to be successful at increasing the current densities, notably in Microbial Fuel Cells (MFCs). [9], [10], [11], [12], [13], [14], [15] The electron transfer from the electroactive bacteria to the anode is indeed affected by the anode properties and its surface modification. The introduction of nitrogen functionalities and/or hydrophilic properties has been suggested to improve electron transfer between electrode and electroactive bacteria.…”

“…The introduction of nitrogen functionalities and/or hydrophilic properties has been suggested to improve electron transfer between electrode and electroactive bacteria. [9] , [10] , [13] , [14] , [15] Only one work uses an affinity approach with grafted boronic acid functionalities targeting the lipopolysaccharide diols of the bacteria outer-membrane. [12] Importantly, apart hydrophilic and/or affinity properties, the chemical layer should also be thin enough in order to maintain fast electron transfer kinetics between the biofilm and the electrode.…”

Anode surface bioaugmentation enhances deterministic biofilm assembly in microbial fuel cells

“…The electroactive biofilm formation process on the anode-surface is critical for an efficient electricity producing MFC (Kumar et al, 2015; Li and Cheng, 2019), and changes in this biofilm consequently strongly affect its electrical output. Hence, the anodic biofilm microbial composition and function has been considered a vital component of the MFC performance, and the metabolic processes that characterize it have been intensively studied (Chae et al 2009; Beecroft et al 2012; Commault et al 2015; Lee et al 2015; Cui et al 2016; Hodgson et al 2016; Paitier et al 2016; Yanuka-Golub et al, 2016; Ishii et al, 2018).…”

Specific Desulfuromonas Strains Can Determine Startup Times of Microbial Fuel Cells

“…Major factors that can limit the electrical output in scaled-up MFCs are directly related to the electroactive microbial community, as well as its electron transport efficiency towards the anode. The anodic biofilm microbial composition has been considered to be a vital component of the MFC performance, and an important parameter for assessing the performance of MFCs and the metabolic processes taking place under different conditions [9][10][11][12][13][14][15]. Anodic biofilm enrichment involves specific selection processes that eventually dictate the biofilm community composition at steady state, i.e., when a stable maximal voltage has been obtained.…”