Figure 4

H ₂ production potential of iRsp1095 with different carbon sources and glutamate as the nitrogen source. (a)Relationship between growth rate and H₂ production. Uptake rates were determined based on a reference chemostat (16 h retention time) fed with succinate (SUR = 1.57 mmol/g DW h) and glutamate (GlUR = 0.75 mmol/g DW h), such that, GlUR was not varied and any other carbon source was supplied by keeping the total number of carbon atoms constant. Experimentally observed H₂ flux from the reference chemostat is shown as a data point. Dashed lines indicate the region that represents the suboptimal growth rates at which the theoretical maximum amount of H₂ is produced for each carbon source. (b)Relationship between substrate reducing power and electrons used in H₂ production (glutamate only case not included). Best fitting lines correspond to three phases of growth in (a) (R² = 1 in all cases).