热醋酸梭状芽胞杆菌发酵葡萄糖和木薯粉产醋酸

摘要

Under constant pH value, the acetic acid production from glucose and cassava fermentation by homoacetogenic Clostridium thermoaceticum was studied. The optimal fermemation model of glucose by C. thermoaceticum was fed-batch fermentation with the addition of excess nitrogen (3 × ) and trace elements, by which 40.2g/L acetic acid was produced in 216 h with a glucose utilization rate of 98％ and a glucose conversion rate of 0. 82g/g. Based on the fermentation model of glucose and enzymolysis conditions of cassava, the fermentation model of cassava was established. Firstly, an appropriate amount of glucoamylase was added into liquefied cassava for fermentation, and then additional amount of glucoamylase was added during fermentation to maintain appropriate glucose concentration. Under above conditions, 47.3g/L acetic acid was produced in 192h with a glucose utilization rate of 94.75％ and a glucose conversion rate of 0. 89g/g. Since the fermentation model of cassava did not need the addition of excess nitrogen and trace elements, and the saccharification was omitted, it would be a perfect fermentation mode for acetic acid production with the improvement of substrate conversion and the shorten of fermentation time.%在恒定pH值条件下,利用同型乙酸菌热醋酸梭状芽胞杆菌(Clostridium thermoaceticum)进行葡萄糖分批发酵、补料分批发酵和木薯粉发酵醋酸的初步研究.最适发酵葡萄糖模式:补糖的同时加入3倍量的氮源和微量元素补料分批发酵.醋酸产量40.2g/L,葡萄糖利用率98%,葡萄糖转化率0.82g/g,发酵时间为216h.结合葡萄糖发酵特点和木薯粉酶解条件摸索出木薯粉发酵条件:木薯液化后直接加入适量的糖化酶进行发酵并在发酵过程中补加适量糖化酶使醪液中葡萄糖浓度保持在一定范围内.醋酸产量47.3g/L,葡萄糖利用率94.75%,葡萄糖转化率0.89g/g,发酵时间192h.不添加过量的氮源和微量元素同时省略了糖化工段,底物转化率提高时间缩短,是比较理想的发酵模式.