Interactions between Clostridium beijerinckii and Geobacter metallireducens in co‐culture fermentation with anthrahydroquinone‐2, 6‐disulfonate (AH 2 QDS) for enhanced biohydrogen production from xylose

To enhance biohydrogen production, Clostridium beijerinckii was co‐cultured with Geobacter metallireducens in the presence of the reduced extracellular electron shuttle anthrahydroquinone‐2, 6‐disulfonate (AH 2 QDS). In the co‐culture system, increases of up to 52.3% for maximum cumulative hydrogen production, 38.4% for specific hydrogen production rate, 15.4% for substrate utilization rate, 39.0% for substrate utilization extent, and 34.8% for hydrogen molar yield in co‐culture fermentation were observed compared to a pure culture of C. beijerinckii without AH 2 QDS. G. metallireducens grew in the co‐culture system, resulting in a decrease in acetate concentration under co‐culture conditions and a presumed regeneration of AH 2 QDS from AQDS. These co‐culture results demonstrate metabolic crosstalk between the fermentative bacterium C. beijerinckii and the respiratory bacterium G. metallireducens and suggest a strategy for industrial biohydrogen production. Biotechnol. Bioeng. 2013; 110: 164–172. © 2012 Wiley Periodicals, Inc.