Effects of culture conditions on the kinetic behavior of 1,3-propanediol fermentation by Clostridium butyricum with a kinetic model.

The effects of culture conditions on the kinetic behavior of 1,3-propanediol (PD) fermentation were investigated with a kinetic model. First, with initial glycerol concentration (S0) increasing, μmax and PD inhibition increased. Glycerol assimilation was harder and a little glycerol was consumed on cell maintenance at high S0. Second, with yeast extract concentration increasing, PD inhibition decreased. However, μmax decreased and glycerol assimilation became harder. It seems that the stimulus effect of yeast extract resulted from decreased PD inhibition. Glycerol amount consumed on cell maintenance also decreased. Third, with temperature decreasing, μmax and PD inhibition decreased. Glycerol assimilation was harder and a little more glycerol was consumed on cell maintenance at low temperature. Fourth, with pH increasing, μmax and PD inhibition decreased. Glycerol assimilation was harder and much more glycerol was consumed on cell maintenance at pH 6.5 and 7.5 than 7.0. This work facilitates further fermentation process optimization.