Probing the robustness of Geobacter sulfurreducens against fermentation hydrolysate for uses in bioelectrochemical systems

In this study, impacts of toxic ions/acids found in real fermentation-hydrolysate on the model exoelectrogenic G. sulfurreducens were investigated. Initially, different concentrations of acetate, butyrate, propionate, Na+, and K+ were tested, individually and in combination, for effects on the planktonic growth, followed by validation with diluted-hydrolysate. Meanwhile, it could be shown that (1) excess Na+ (>= 100 mM) causes inhibition that can be reduced by K+ replacement, (2) butyrate (>= 10 mM) induces higher toxicity than propionate, and (3) hydrolysate induces synergistic inhibition to G. sulfurreducens where organic constituents contributed more than Na+. Afterwards, compared with impacts on planktonic cells, the pre-enriched anodic biofilm of G. sulfurreducens in BESs showed higher robustness against diluted-hydrolysate, achieving current densities of 1.4-1.7 A/m(2) (at up to similar to 30 mM butyrate and propionate as well as similar to 240 mM Na+). As a conclusion, using G. sulfurreducens in BESs dealing with fermentation-hydrolysate can be regulated for efficacious energy recovery.

Automated summary

This study investigated the impacts of toxic ions/acids in real fermentation-hydrolysate on the model exoelectrogenic G. sulfurreducens. Different concentrations of acetate, butyrate, propionate, Na+, and K+ were tested individually and in combination to understand their effects on planktonic growth. The study found that excess Na+ (>= 100 mM) causes inhibition that can be reduced by K+ replacement, butyrate (>= 10 mM) induces higher toxicity than propionate, and hydrolysate induces synergistic inhibition where organic constituents are more significant than Na+. The research concluded that using G. sulfurreducens in bioelectrochemical systems can effectively recover energy from fermentation-hydrolysate.