title: A defined co-culture of Geobacter sulfurreducens and Escherichia coli in a membrane-less microbial fuel cell.
abstract: Wastewater-fed microbial fuel cells (MFCs) are a promising technology to treat low-organic carbon wastewater and recover part of the chemical energy in wastewater as electrical power. However, the interactions between electrochemically active and fermentative microorganisms cannot be easily studied in wastewater-fed MFCs because of their complex microbial communities. Defined co-culture MFCs provide a detailed understanding of such interactions. In this study, we characterize the extracellular metabolites in laboratory-scale membrane-less MFCs inoculated with Geobacter sulfurreducens and Escherichia coli co-culture and compare them with pure culture MFCs. G. sulfurreducens MFCs are sparged to maintain anaerobic conditions, while co-culture MFCs rely on E. coli for oxygen removal. G. sulfurreducens MFCs have a power output of 128 mW m(-2) , compared to 63 mW m(-2) from the co-culture MFCs. Analysis of metabolites shows that succinate production in co-culture MFCs decreases current production by G. sulfurreducens and that the removal of succinate is responsible for the increased current density in the late co-culture MFCs. Interestingly, pH adjustment is not required for co-culture MFCs but a base addition is necessary for E. coli MFCs and cultures in vials. Our results show that defined co-culture MFCs provide clear insights into metabolic interactions among bacteria while maintaining a low operational complexity.
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St, Toronto, Ontario, M5S 3E5, Canada.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Bourdakos
authors.forename: Enrico
authors.initials: E
authors.lastname: Marsili
authors.forename: Radhakrishnan
authors.initials: R
authors.lastname: Mahadevan
mesh_terms: D001674:Bioelectric Energy Sources / Q000382:microbiology*; D018920:Coculture Techniques / Q000379:methods*; D004926:Escherichia coli / Q000378:metabolism*; D045302:Geobacter / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D062065:Wastewater
chemical_list: D005947:Glucose; D062065:Wastewater
keywords: Escherichia coli; Geobacter sulfurreducens; co-culture MFC