Improving ethanol productivity by modification of glycolytic redox factor generation in glycerol-3-phosphate dehydrogenase mutants of an industrial ethanol yeast

  • Zhong-peng Guo
  • Liang Zhang
  • Zhong-yang Ding
  • Zheng-Xiang Wang
  • Gui-Yang Shi
Original Paper

Abstract

The GPD2 gene, encoding NAD+-dependent glycerol-3-phosphate dehydrogenase in an industrial ethanol-producing strain of Saccharomyces cerevisiae, was deleted. And then, either the non-phosphorylating NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPN) from Bacillus cereus, or the NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Kluyveromyces lactis, was expressed in the obtained mutant AG2 deletion of GPD2, respectively. The resultant recombinant strain AG2A (gpdPPGK-gapN) exhibited a 48.70 ± 0.34% (relative to the amount of substrate consumed) decrease in glycerol production and a 7.60 ± 0.12% (relative to the amount of substrate consumed) increase in ethanol yield, while recombinant AG2B (gpdPPGK-GAPDH) exhibited a 52.90 ± 0.45% (relative to the amount of substrate consumed) decrease in glycerol production and a 7.34 ± 0.15% (relative to the amount of substrate consumed) increase in ethanol yield compared with the wild-type strain. More importantly, the maximum specific growth rates (μmax) of the recombinant AG2A and AG2B were higher than that of the mutant gpd2Δ and were indistinguishable compared with the wild-type strain in anaerobic batch fermentations. The results indicated that the redox imbalance of the mutant could be partially solved by expressing the heterologous genes.

Keywords

Saccharomyces cerevisiae Glycerol-3-phosphate dehydrogenase NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase Glycerol production Ethanol yield 

Copyright information

© Society for Industrial Microbiology 2010

Authors and Affiliations

  • Zhong-peng Guo
    • 1
  • Liang Zhang
    • 1
  • Zhong-yang Ding
    • 1
  • Zheng-Xiang Wang
    • 1
  • Gui-Yang Shi
    • 1
  1. 1.The Key Laboratory of Industrial Biotechnology, Ministry of Education, Center for Bioresources and Bioenergy, School of BiotechnologyJiangnan UniversityWuxiPeople’s Republic of China

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