固定化 K 字酵母酒精生成动力学及性质研究

KINETICS AND CHARACTERISTICS OF ETHANOL FORMATION BY IMMOBILIZED K YEAST CELLS

从酒精发酵的代谢机理出发,在引入酶动力学、提出联合抑制的可逆图解式后导得理论速率方程。依据实验对固定化 K 字酵母生物催化剂进行的酒精生成动力学之研究表明:该过程具有酒精的不可逆及表现为随其浓度而变化的非竞争型抑制,葡萄糖则呈现为反竞争性抑制,及动力学参数随底物初始浓度变化等特性。提出的酒精生成动力学模型基础方程为联合抑制方程,所确定的参数值具有高度的相关性。且预测效果良好,其中酒精浓度随反应器高度分布的预测误差仅为18.75%,从而推知反应器内流体流动形式接近于平推流。

A mathematical model describing the kinetics of formation in a K yeast cell immobilized tubular fermenter was established.An experimental procedure was used to determine the parameters of the model and the kinetic characteristics was discussed. The concentrations of ethanol were 45.4 g/L,71.1 g/L,90.6 g/L for the initail concentra- tions of glucose 100 g/L,150 g/L,200 g/L,respectively.These means that the conversion of glu- cose to ethanol were about 90%. Two tubular reactors,Φ25.4mm ×600mm and Φ25.4mm×400mm glass columns,and all packed with Ca-alglnate ball in a diameter of 3-4mm,were used in experiments. The model was expressed as a combined inhibition,i.e.ethanol in noncompetitive inhibition with irreversible performance and glucose in uncompetitive inhibition: ■ Using the Marquart method to treat the fermentation data,it was found that the parameters were well correlated.To the 600mm column,the average deviations of the calculated values of the model to the experimental data were 1.34% and 6.38%,while to the 400m column,the devia- tions of the model predictions were 5.80%、8.11% when the initial concentrations of glucose were 150g/L、200g/L,respectively.The predicted deviation of ethanol concentration profile along the column height was 18.75%.Therefore,it is expected that the flow in the column is of piston flow pattern.