Segregation of the Anodic Microbial Communities in a Microbial Fuel Cell Cascade

Abstract

Metabolic interactions within microbial communities are essential for the efficient degradation of complex organic compounds, and underpin natural phenomena driven by microorganisms, such as the recycling of carbon-, nitrogen-, and sulfur-containing molecules. These metabolic interactions ultimately determine the function, activity and stability of the community, and therefore their understanding would be essential to steer processes where microbial communities are involved. This is exploited in the design of microbial fuel cells (MFCs), bioelectrochemical devices that convert the chemical energy present in substrates into electrical energy through the metabolic activity of microorganisms, either single species or communities. In this work, we analyzed the evolution of the microbial community structure in a cascade of MFCs inoculated with an anaerobic microbial community and continuously fed with a complex medium. The analysis of the composition of the anodic communities revealed the establishment of different communities in the anodes of the hydraulically connected MFCs, with a decrease in the abundance of fermentative taxa and a concurrent increase in respiratory taxa along the cascade. The analysis of the metabolites in the anodic suspension showed a metabolic shift between the first and last MFC, confirming the segregation of the anodic communities. Those results suggest a metabolic interaction mechanism between the predominant fermentative bacteria at the first stages of the cascade and the anaerobic respiratory electrogenic population in the latter stages, which is reflected in the observed increase in power output. We show that our experimental system represents an ideal platform for optimization of processes where the degradation of complex substrates is involved, as well as a potential tool for the study of metabolic interactions in complex microbial communities.

Evolving Microbial Communities in Cellulose-Fed Microbial Fuel Cell

“…The representatives of Bacteroidetes have already been reported to be abundant in anodic communities as fermenters [36]. Among Bacteroidetes the most abundant genera were Parabacteroides and Proteiniphilum, which are known as degrading polysaccharides and xylans to acetate and succinate [35,43]. Members of Bacteroidetes have also been shown to be enriched in enzymes targeting carbohydrates what allows to utilize cellulose, xylans, pectin and galaxans [44].…”

“…Amongha Firmicutes, the most abundant genera were Clostridium and Catonella (both with a relative abundance above 20%), (Figure 4b). Clostridium genus was previously found to be dominant in the community of a single-chamber MFC fed with lignocellulosic substrate [35], a single-chamber MFC fed with sucrose [36], and two-chamber MFC fed with acetate [37]. The highest relative abundance of genera in the bacteria consortium …”

Effect of the chemical composition of filter media on the microbial community in wastewater biofilms at different temperatures

“…63,64 These parameters are related to the extent of wastewater treatment and are provided in Table S2 †. The results indicate that BOD 5 of wastewater is strongly influenced by the presence of both heterotrophs and autotrophs in the community.…”

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).…”