Efficient, D-glucose insensitive, growth on D-xylose by an evolutionary engineered Saccharomyces cerevisiae strain

Jeroen G. Nijland, Xiang Li, Hyun Yong Shin, Paul P. de Waal, Arnold J. M. Driessen*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)
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Abstract

Optimizing D-xylose consumption in Saccharomyces cerevisiae is essential for cost-efficient cellulosic bioethanol production. An evolutionary engineering approach was used to elevate D-xylose consumption in a xylose-fermenting S. cerevisiae strain carrying the D-xylose-specific N367I mutation in the endogenous chimeric Hxt36 hexose transporter. This strain carries a quadruple hexokinase deletion that prevents glucose utilization, and allows for selection of improved growth rates on D-xylose in the presence of high D-glucose concentrations. Evolutionary engineering resulted in D-glucose-insensitive growth and consumption of D-xylose which could be attributed to glucose insensitive D-xylose uptake via a novel chimeric Hxt37 N367I transporter that emerged from a fusion of the HXT36 and HXT7 genes, and a down regulation of a set of Hxt transporters that mediate glucose sensitive xylose transport. RNA sequencing revealed the down-regulation of HXT1 and HXT2 which, together with the deletion of HXT7, resulted in a 21% reduction of the expression of all plasma membrane transporters genes. Morphological analysis showed an increased cell size and corresponding increased cell surface area of the evolved strain, which could be attributed to genome duplication. Mixed strain fermentation of the D-xylose-consuming strain DS71054-evo6 with the D-glucose consuming CEN.PK113-7D strain resulted in decreased residual sugar concentrations and improved ethanol production yields compared to a strain which sequentially consumes D-glucose and D-xylose.

Original languageEnglish
Article numberfoz083
Number of pages10
JournalFems Yeast Research
Volume19
Issue number8
Early online date29-Nov-2019
DOIs
Publication statusPublished - Dec-2019

Keywords

  • Sugar transport
  • D-xylose transporter
  • bioethanol
  • co-fermentation
  • yeast
  • YEAST HEXOSE TRANSPORTERS
  • CO-CONSUMPTION
  • FERMENTATION
  • METABOLISM
  • IDENTIFICATION
  • EXPRESSION
  • MUTATIONS
  • ETHANOL
  • ERRORS
  • GENE

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