Electro‐fermentation triggering population selection in mixed‐culture glycerol fermentation

Abstract

SummaryElectro‐fermentation is a new technique that could be used to influence the global metabolism in mixed‐culture fermentation. In this study, a mixed‐culture cathodic electro‐fermentation of glycerol was investigated. Both microbial community structure and metabolic patterns were altered when compared to standard fermentation. This microbial population shift was more significant when the working electrodes were pre‐colonized by Geobacter sulfurreducens, before electro‐fermentation. The electro‐fermenting microbial community was more efficient for producing 1,3‐propanediol with an improved yield of 10% when compared with fermentation controls. Such improvement did not require high energy and total electron input represented < 1% of the total electron equivalents provided only by glycerol. A linear model was developed to estimate the individual metabolic pattern of each operational taxonomic unit. Application of this model compared to the experimental results suggests that the changes in global metabolism were supported by bacterial population selection rather than individual metabolism shift. This study shows for the first time that both fermentation pattern and bacterial community composition can be influenced by electro‐fermentation conditions.

A Comprehensive Understanding of Electro-Fermentation

“…This sudden increase in the pH caused a significant decrease in the production of methane by 43%. In contrast to the above study, in another research [89], it was observed that when using a two-chamber cell with a short HRT for about 3 days, with an applied voltage of 0.6 V, a significant increase was observed in methane production. Nevertheless, voltage conditions of 1.0 V and 2.0 V decreased the production of methane by 37%.…”

Predicting Accumulation of Intermediate Compounds in Nitrification and Autotrophic Denitrification Processes: A Chemical Approach

“…Therefore, it is reasonable to think that the redox potential value inside bioreactors can affect the metabolite generation and, therefore, the spectrum of products obtained depending on the extracellular redox conditions. In fact, electrofermentation is a novel technique that is being used to change the overall performance in mixed-culture fermentations, by altering both microbial community structure and metabolic patterns [30]. Also, electrochemical control of the redox potential in mixed culture bioreactors has been shown to regulate microbial metabolites production [31].…”

Microbial electrochemical technologies: maturing but not mature

“…Here, with their recent work published in the issue, Moscoviz et al. () proved that the electro‐fermenting microbial community was more efficient for producing 1,3‐propanediol when compared with fermentation controls…”