Dual modulation of glucose 6-phosphate metabolism to increase NADPH-dependent xylitol production in recombinant Saccharomyces cerevisiae
- 作者：Yong-Joo Oh ; Tae-Hee Lee ; Sung-Haeng Lee ; Eun-Joong Oh ; Yeon-Woo Ryu ; Myoung-Dong Kim ; Jin-Ho Seo
- 刊名：Journal of Molecular Catalysis B ; Enzymatic
- 出版年：2007
- 期刊代码：55_13811177
- 类别：ce
- 出版时间：1 June 2007
- 卷：47
- 期：1-2
- 页码：37-42
- 文件大小：332 K
摘要
To increase the metabolic flux toward the NADPH-generating pentose phosphate pathway in a recombinant Saccharomyces cerevisiae strain that harbors the xylose reductase gene from Pichia stipitis, expression of phosphoglucose isomerase (PGI) encoded by the PGI1 gene was modulated by a promoter replacement using the ADH1 promoter. Although the ADH1 promoter down-regulated PGI expression in glucose-limited condition, the decline of PGI activity did not exert a profound influence on xylitol production in a series of glucose-limited fed-batch cultivations. However, simultaneous enforcement of glucose 6-phosphate dehydrogenase (G6PDH) activity and attenuation of phosphoglucose isomerase activity worked in a cooperative manner to increase xylitol production and to reduce utilization of cosubstrate required for xylitol production in a glucose-limited fed-batch cultivation of the PGI mutant strain with an enhanced G6PDH activity. An 1.9-fold increase in specific xylitol productivity of 0.34 ± 0.03 g/g cells h was achieved compared with the control strain containing xylose reductase only.