Biotechnology Bulletin ›› 2014, Vol. 0 ›› Issue (2): 153-160.

• Papers • Previous Articles     Next Articles

Construction of Recombinant Saccharomyces cerevisiae Strains Through Expressing the Key Genes in the Xylose Metabolism Under the Control of Different Promoters for Co-fermentation Glucose and Xylose

Jin Yi, Wang Zhen, Mo Chunling, Yang XiuShan, Tian Shen   

  1. College of Life ScienceCapital Normal UniversityBeijing 100048)
  • Received:2013-08-28 Online:2014-02-27 Published:2014-02-27

Abstract: In order to obtain a recombinant yeast strain which can co-ferment both xylose and glucose, the key genes of enzymes in the xylose metabolism were cloned and transformed into Saccharomyces. cerevisiae Y5. The XYL1 and XYL2 genes from Pichia stipitis CBS6054 were placed under the PGKp, which is a constitutive strong promoter;endogenesis XKS1 gene from S.cerevisiae Y5 was controlled by HXK2p and the native promoter XKS1p, respectively. We measured the activity of XR、XDH and XK and evaluated the xylose-fermenting abilities of the engineered strains. The highest xylulokinase activity was observed in the strain Y5-X3-1 whose XKS1 was controlled by HXK2p. The activity of enzyme ratio was 1∶5∶4 between XR, XDH and XK. Furthermore, the xylose consumption of S.cerevisiae Y5-X3-1 was 5 times as the host strain during co-fermentation, and the highest ethanol concentration was 24.35 g/L, which correspond to 73% of the theoretical value.