pH值对Clostridium beijerinckii发酵联产丁醇与氢气的影响及其动力学模型

Effects of pH Value on Co-production of Butanol and Hydrogen by Clostridium beijerinckii Fermentation and Kinetic Modeling

实验考察了pH值对拜氏梭菌ClostridiumbeijerinckiiIB4厌氧发酵产丁醇及氢气的影响．结果表明，氢气与丁醇的发酵均属部分生长偶联型．pH=6．0有利于发酵前期（0～1611）菌体生长及产氢，但后期代谢受抑制；pH=4．9时会导致菌体生长缓慢及代谢活力下降；pH=5．2时丁醇及氢气产量分别达12．06g／L和5．76L／L，比不调控pH值时提高11．87％及15．43％．在此基础上建立了菌体生长、丁醇积累及氢气生成的分批发酵动力学方程，模型拟合度较高，pH=5．2时菌体停止生长后丁醇生成能力系数比对照增加105．45％，最大产氢速率比对照增加7．45％．

The effects of pH value on co-production of butanol and hydrogen by fermentation with Clostridium beijerinckii IB4 were studied. The results demonstrated that both hydrogen and butanol fermentation was partially related to growth. When pH value was controlled at 6.0, cells grew well and hydrogen was accumulated rapidly during the initial fermentation phase （0-16 h）. However, clostridial metabolism was inhibited by the accumulation of organic acids during later fermentation phase. When pH value was at lower value of 4.9, cells grew slowly and metabolic activities were restrained. When pH value was controlled at 5.2, butanol accumulation and hydrogen evolution achieved 12.06 g/L and 5.76 L/L, respectively, which were 11.87% and 15.43% higher than those without pH value control. The kinetic models on cell growth, butanol and hydrogen production in batch fermentation were established, the kinetic coefficient R2 demonstrated the fitting of the models was good. Making comparison among kinetic parameters, constant coefficient, indication of butanol synthesis ability after cells growth ceased, was improved by 105.45%, and constant coefficient, indication of maximum hydrogen production rate was improved by 7.45%, when pH value was controlled at 5.2,