Stimulation of electricity production in microbial fuel cells via regulation of syntrophic consortium development

Production of electricity from wastewater in microbial fuel cells is possible due to the cooperation of hydrolytic, fermentative, and electrogenic microorganisms coexisting in a consortium. In this article, we present results that indicate that we can stimulate electrical current production from wastewater, from which power could not be produced without influencing the growth of a microbial consortium through preconditioning. The wood industry wastewater was thermally preconditioned at 45 °C before introducing it to microbial fuel cells which resulted in changing microbial consortium composition by the development of new species. In the anodes of microbial fuel cells that were fed preconditioned wastewater, we identified, by the means of metagenomic analysis, mixed fungi-bacteria syntrophic consortium that was capable of producing electricity from wood industry wastewater. The developed syntrophic consortium was dominated by fungi of the Trichocomaceae sp. and two bacteria species: Achromobacter insolitus and Geobacter sulfurreducens. None of these species were present in raw wastewater. Power was not generated in microbial fuel cells that were fed raw wastewater, but wastewater preconditioning stimulated power production at 0.33 W/m2 what responded to 1 A/m2 current density. The developed consortium decomposed cellulose present in wastewater into glucose and fermented it into acids and alcohols. We showed that stimulation of power production may be driven through substrate preconditioning before it is used in microbial fuel cells. By selecting growth conditions for a consortium, we may regulate its microbial composition and facilitate production of an electrical current from substrates that could not previously be used in microbial fuel cells.