Effect of MIG1 Gene Deletion on Lactose utilization in the Lac+ S.cerevisiae

摘要

Mig1 is a zinc-finger DNA-binding protein that plays a critical role in glucose repression in yeast ethanol fermentation.In this work,strains S.cerevisiae EY-510 (Lac+) and its derivitive RY-510 with MIG1 gene deletion mutation were used to investigate their ability to hydrolyze lactose and galactose metabolism.In contrast to the EY-510,RY- 510 consumed glucose and galactose simultaneously,in which 16.5％ galactose was consumpted.The fermentation period and ethanol productivity of RY-510 was 168h and 0.357,respectively,in comparision with 252h and 0.348 of EY-510 in lactose medium.And in whey chesse powder medium,compared with EY-510,the ethanol concentration of RY-510 increased by 35.2％,while fermentation time and residual lactose concentration decreased by 26.9％ and 77.9％,respectively.This suggested that MIG1 gene deletion could improve the lactose/whey fermentation efficiency and shorten fermentation period.To relieve the glucose repression is a good way for high efficent lactose-consuming strain breeding.