Figure 1

The effect of varying COI on the biomass production and electron transfer rates. The reducing equivalent supplying rates in the (A) DET, (B) MET or (C) Mixed mode, and the biomass yields in the cases of (A-C), as functions of weighting ratios of the electron transfer rate versus biomass in G. sulfurreducens metabolic model. A series of coefficients of importance (COI), 1,2,20, 200, 400, 900, 1500 and 3000 were applied for the electron transfer flux. The changing trends of electron transfer rates in the tree modes are compared to those of the corresponding biomass yields. COI is the stoichiometry representation used in the compound objective function. The higher the COI means the priority for associated electron transfer reaction is higher. The reducing equivalent represents NADH in the MET mode, whereas it denotes an assumed product of the reaction catalysed by cytochrome c reductase for the DET mode.