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High-level β-carotene production from xylose by engineered Saccharomyces cerevisiae without overexpression of a truncated HMG1 (tHMG1)
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  • LIANG SUN,
  • Christine Atkinson,
  • Ye-Gi Lee,
  • Yong-Su Jin
LIANG SUN
University of Illinois at Urbana-Champaign
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Christine Atkinson
University of Illinois at Urbana-Champaign
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Ye-Gi Lee
University of Illinois at Urbana-Champaign
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Yong-Su Jin
University of Illinois at Urbana-Champaign
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Abstract

β-carotene is a natural pigment and health-promoting metabolite, and has been widely used in the nutraceutical, feed and cosmetic industries. Here, we engineered a GRAS yeast Saccharomyces cerevisiae to produce β-carotene from xylose, the second most abundant and inedible sugar component of lignocellulose biomass. Specifically, a β-carotene biosynthetic pathway containing crtYB, crtI and crtE from Xanthophyllomyces dendrorhous were introduced into a xylose-fermenting S. cerevisiae. The resulting strain produced β-carotene from xylose at a titer three-fold higher than from glucose. Interestingly, overexpression of tHMG1, which has been reported as a critical genetic perturbation to enhance metabolic fluxes in the mevalonate (MVA) pathway and β-carotene production in yeast when glucose is used, did not further improve the production of β-carotene from xylose. Through fermentation profiling, metabolites analysis and transcriptional studies, we found the advantages of using xylose as a carbon source instead of glucose for β-carotene production to be a more respiratory feature of xylose consumption, a larger cytosolic acetyl-CoA pool, and up-regulated expression levels of rate-limiting genes in the β-carotene producing pathway, including ACS1 and HMG1. As a result, 772.81 mg/L of β-carotene was obtained in a fed-batch bioreactor culture with xylose feeding. Considering the inevitable production of xylose at large scales when cellulosic biomass-based bioeconomy is implemented, our results suggest xylose utilization is a promising strategy for overproduction of carotenoids and other isoprenoids in engineered S. cerevisiae.

Peer review status:ACCEPTED

30 Jan 2020Submitted to Biotechnology and Bioengineering
31 Jan 2020Submission Checks Completed
31 Jan 2020Assigned to Editor
03 Feb 2020Reviewer(s) Assigned
25 Mar 2020Review(s) Completed, Editorial Evaluation Pending
25 Mar 2020Editorial Decision: Revise Major
24 May 20201st Revision Received
26 May 2020Assigned to Editor
26 May 2020Submission Checks Completed
27 May 2020Reviewer(s) Assigned
12 Jun 2020Editorial Decision: Revise Minor
12 Jun 2020Review(s) Completed, Editorial Evaluation Pending
30 Jun 20202nd Revision Received
01 Jul 2020Submission Checks Completed
01 Jul 2020Assigned to Editor
08 Jul 2020Reviewer(s) Assigned
15 Jul 2020Review(s) Completed, Editorial Evaluation Pending
15 Jul 2020Editorial Decision: Accept