固定化细胞乳酸发酵动力学及工艺的研究

Lactic Acid Production and a Kinetic Study of Immobilized L. delbrueckii

本文对海藻酸钙固定化德氏乳酸杆菌的间歇发酵动力学进行了探讨,并对固定化细胞高糖浓度发酵以及外循环固定化细胞反应器连续发酵工艺条件进行了研究。结果表明:固定化不改变细胞的最适生长温度和pH;底物和产物均对细胞生长有抑制作用;固定化细胞生长的饱和常数和抑制常数增大,比生长速率减小,产酸速率增加;高糖浓度发酵最适工艺条件为初糖浓度120～130g/l,发酵时间68～72h,发酵液中乳酸浓度可达100g/l;外循环固定化细胞反应器连续发酵最适工艺条件为初糖浓度50g/l,稀释速率0.048～0.09l/h,转化率达78％。

The kinetic study of batch fermentation by immobilized Lactoba--cillus delbrueckii in Ca-alginate was conducted and compared with free cells. Batch processes of high substrate concentration and continuous fermentation in recycle packed bed bioreactor were also studied. Com-pa red to free cells,immobilized cells show higher lactic acid formation rate but the specific growth rate appears to be comparatively low. Immobili -zation does not change the best growth temperature and pH. Both of substrate and product have inhibitory effects on the fermentation. The constants of saturation and inhibition for the growth of immobilized cells increase. The best process from high substrate fermentation was glucose 120~l30g/l and fermentation time 68~72 hours, and the lactic acid reached l00g/l.The best run of continuous processes was substrate 50g/l and dilution rate 0.048-0.09 1/h, and the yield reached 78%.