Study on Curdlan Fermentation Kinetics of Alcaligenes faecalis under Chemostat Cultivation

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=0.36S/(2.27+S),and the kinetic model between the specific biosynthesis rate of curdlan and the ammonium concentration was q_p=0.0612S/(2.27+S)+0.14×(1-S/64.94),and the kinetic model of glucose consumption rate to the specific yield was q_s=1.5 μ+q_p+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.