A kinetic approach to anaerobic hydrogen-producing process.

Kinetics of hydrogen production from sucrose by mixed anaerobic cultures was investigated, and the Gompertz model was modified to describe the growth of hydrogen-producing microorganisms, consumption of substrate and formation of product in this work. A modified Gompertz model could adequately fit the experimental results. The effects of pH, temperature and the ratio of the initial substrate concentration to initial biomass concentration (S(0)/X(0)) on the maximum specific microbial growth rate (micro(m)) were evaluated using a response-surface methodology. Experimental results show that pH, temperature and S(0)/X(0) all had an influence on micro(m). The effect of pH and the second-order effect of pH and temperature were significant. A maximum micro(m) of 0.078 h(-1) was estimated under the optimum conditions of pH 5.5, temperature 34.6 degrees C and S(0)/X(0) of 4.3g/g-VSS. Modeling of microbial growth, substrate consumption and product formation was useful for optimizing the anaerobic hydrogen-producing process.