玉米浆在产甘油假丝酵母甘油发酵中的作用机理

以复合培养基和合成培养基进行比较发酵,研究了玉米浆在产甘油假丝酵母甘油发酵过程中的作用机理。结果表明:玉米浆中的磷、氮和微量元素是影响产甘油假丝酵母甘油发酵的3个关键因素。当玉米浆磷浓度为121·75mg/L(玉米浆浓度为14g/L),最大甘油转化率达到53·44%。玉米浆磷可以调节EMP途径与HMP途径之间碳架代谢流的分布,随着玉米浆浓度进一步增加,过量磷能抑制HMP途径而激活EMP途径,因而复合培养基各项发酵参数的变化非常显著。玉米浆氮对磷的调节功能有协同作用,但并不是产甘油假丝酵母甘油发酵的理想氮源。玉米浆中的微量元素能够显著提高葡萄糖的消耗速率、促进菌体的生长和增加甘油的产量。

Mechanism of Corn Steep Liquor during Glycerol Fermentation by Candida glycerinogenes

Using chemically defined medium as the control, mechanism of corn steep liquor (CSL) in complex medium during glycerol production by Candida glycerinogenes was studied.The results showed that there were three key factors in CSL that had some great influences on glycerol fermentation of C.glycerinogenes, including phosphorus, nitrogen, and trace elements.The maximum glycerol yield of 53.44% was achieved at an optimal phosphorus concentration of 121.75mg/L, where the CSL concentration was 14g/L.Phosphorus in CSL could control the distribution of carbon metabolism flux between EMP pathway and HMP pathway.With the increase in CSL concentrations, superfluous phosphorus could restrain HMP pathway and activate EMP pathway, thus resulting in remarkable changes in various fermentation parameters of complex medium.Nitrogen in CSL could play a cooperative role in the regulative function of phosphorus.However, it was not a suitable nitrogen source for C.glycerinogenes.Trace elements in CSL could markedly improve the glucose consumption rate, accelerate the cell growth, and enhance the glycerol yield.