恒化培养条件下粪产碱杆菌凝胶多糖的发酵动力学研究

Study on Curdlan Fermentation Kinetics of Alcaligenes faecalis under Chemostat Cultivation

通过恒化培养实验研究了不同稀释速率下粪产碱杆菌(Alcaligenes faecalis)的生理代谢特性变化,利用Monod、Luedeking-Piret、Herbert-pirt模型分析了粪产碱杆菌的生长、多糖合成以及底物葡萄糖消耗的动力学变化。结果表明,在铵离子限制条件下的菌体比生长速率与铵离子浓度之间的动力学模型为μ=0.36S/(2.27+S),凝胶多糖比产率与铵离子浓度间的动力学模型为qp=0.0612S/(2.27+S)+0.14×(1-S/64.94),以及比底物葡萄糖消耗速率与比产率的动力学模型为:qs=1.5μ+qp+0.0625。通过对恒化培养模型及生产菌生理代谢参数的分析,统计分析表明该生产菌最佳限制性铵离子浓度为5.75 mg/L,得到控制最适比生长速率为0.21 h-1时,A.faecalis的最高产率可达到0.85 g/L/h,并且最大比产率高达0.171 g/g/h,产率和比产率与批培养过程相比分别提升了118%和200%,能够显著提升凝胶多糖的生产效率。

In this paper,the physiological and metabolic characteristic of A. faecalis at different dilution rates through chemostat cultivation had been studied. The metabolic kinetic parameters on cell growth,curdlan biosynthesis and substrate glucose consumption were obtained with Monod,Luedeking-Piret and Herbert-pirt models. The results showed that the kinetic model for the cell growth rate to ammonium concentration under ammonium ion restriction conditions was μ=0.36 S/(2.27+S),and the kinetic model between the specific biosynthesis rate of curdlan and the ammonium concentration was qp=0.0612 S/(2.27+S)+0.14×(1-S/64.94),and the kinetic model of glucose consumption rate to the specific yield was qs=1.5 μ+qp+0.0625. The statistic physiological metabolic parameters on A. faecalis demonstrated that the optimal ammonium-limited concentration was 5.75 mg/L.And under the specific cell growth rate at 0.21 h-1,the highest yield and maximum specific production rate of cudlan could reach 0.85 g/L/h and 0.17 g/g/h,which was 118% and 200% higher than that under batch culture process respectively. It would significantly improve the efficiency of curdlan production.