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Transcriptomic changes induced by de-activation of lower glycolysis and its advantage on pentose sugar metabolism in Saccharomyces cerevisiae
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  • Minhye Shin,
  • Heeyoung Park,
  • Sooah Kim,
  • Eun Joong Oh Oh,
  • Deokyeol Jeong,
  • Clarissa Florencia,
  • Kyoung Heon Kim,
  • Yong-Su Jin,
  • Soo Rin Kim
Minhye Shin
Korea University
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Heeyoung Park
Kyungpook National University
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Sooah Kim
Jeonju University
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Eun Joong Oh Oh
University of Colorado Boulder
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Deokyeol Jeong
Kyungpook National University
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Clarissa Florencia
University of Illinois at Urbana-Champaign
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Kyoung Heon Kim
Korea University
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Yong-Su Jin
University of Illinois at Urbana-Champaign
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Soo Rin Kim
Kyungpook National University
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Abstract

As a microbial host for cellulosic biofuel production, Saccharomyces cerevisiae needs to be engineered to express a heterologous xylose pathway. However, it has been challenging to optimize the engineered strain for efficient and rapid fermentation of xylose. Deletion of PHO13 (pho13) has been reported to be a crucial genetic perturbation for improving xylose fermentation. A confirmed mechanism of the pho13-positive effect on xylose fermentation is that the deletion of PHO13 transcriptionally activates the genes in the non-oxidative pentose phosphate pathway (PPP). In the present study, we reported that a pho13-positive effect was not observed from a couple of engineered strains, among the many others we have examined. To extend our knowledge of pho13-mediated metabolic regulation, we performed genome sequencing of pho13-negative strains. We identified a loss-of-function mutation in GCR2 responsible for the pho13-negative phenotype. Gcr2 is a transcriptional activator of the lower glycolytic pathway. Thus, the deletion of GCR2 (gcr2) led to deactivation of lower glycolysis as confirmed by RNA-seq. Also, gcr2 resulted in the up-regulation of PPP genes, which explains the improved xylose fermentation of gcr2 mutants. As pho13 and gcr2 cause similar transcriptional changes with PPP genes, there was no synergistic effect between pho13 and gcr2 for improving xylose fermentation. The present study identified GCR2 as a new knockout target to improve xylose fermentation and cellulosic biofuel production.

Peer review status:UNDER REVIEW

12 Sep 2020Submitted to Biotechnology and Bioengineering
12 Sep 2020Assigned to Editor
12 Sep 2020Submission Checks Completed
15 Sep 2020Reviewer(s) Assigned