Evaluation of co-culture sustainability and hydrogen production in an integrated fermentative microbial electrolysis cell

• Main Author: Wrana, Nathan
• Other Authors: Levin, David (Biosystems Engineering)
• Language: en_US
• Published: 2011
• Subjects: Hydrogen; Microbial electrohydrogenesis; Co-culture; Fermentation
• Online Access: http://hdl.handle.net/1993/4456

The relationship between the cellulolytic Clostridium termitidis and the electrogenic Geobacter sulfurreducens was evaluated in terms of co-culture sustainability and hydrogen production. Batch co-culture experiments in triplicate balch tubes were conducted using cellobiose as the sole carbon source and fumarate as a terminal electron acceptor. Despite high initial concentrations of acetate, no formate and very low H2 concentrations were detected, supporting the hypothesis that a syntrophic association exists between both bacteria. Co-culture growth characterization experiments were repeated in three microbial electrolysis cells and cellobiose as the sole carbon source. Initially, 9.7 mol-H2 mol-1-glucose was produced. However, a sustainable co-culture could not be maintained despite efforts to reduce reactor temperature and triple the medium’s buffering capacity. Strategies to achieve a sustainable co-culture are to minimize the carbon flux through C. termitidis by using complex substrates, maintain neutral operating conditions, and introduce acetogenic bacteria to control the flux of metabolic intermediates.