Original Paper

Journal of Industrial Microbiology & Biotechnology

, Volume 38, Issue 8, pp 935-943

First online:

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

  • Zhong-peng GuoAffiliated withThe Key Laboratory of Industrial Biotechnology, Ministry of Education, Center for Bioresources and Bioenergy, School of Biotechnology, Jiangnan University
  • , Liang ZhangAffiliated withThe Key Laboratory of Industrial Biotechnology, Ministry of Education, Center for Bioresources and Bioenergy, School of Biotechnology, Jiangnan University
  • , Zhong-yang DingAffiliated withThe Key Laboratory of Industrial Biotechnology, Ministry of Education, Center for Bioresources and Bioenergy, School of Biotechnology, Jiangnan University
  • , Zheng-Xiang WangAffiliated withThe Key Laboratory of Industrial Biotechnology, Ministry of Education, Center for Bioresources and Bioenergy, School of Biotechnology, Jiangnan University
  • , Gui-Yang ShiAffiliated withThe Key Laboratory of Industrial Biotechnology, Ministry of Education, Center for Bioresources and Bioenergy, School of Biotechnology, Jiangnan University Email author 

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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 (gpdP PGK -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 (gpdP PGK -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 (μ max) 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