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Metab Eng. 2014 May;23:92-9. doi: 10.1016/j.ymben.2014.02.003. Epub 2014 Feb 10.

Metabolic engineering of a Saccharomyces cerevisiae strain capable of simultaneously utilizing glucose and galactose to produce enantiopure (2R,3R)-butanediol.

Author information

1
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Energy Biosciences Institute, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
2
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Energy Biosciences Institute, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States. Electronic address: zhao5@illinois.edu.

Abstract

2,3-Butanediol (BDO) is an important chemical with broad industrial applications and can be naturally produced by many bacteria at high levels. However, the pathogenicity of these native producers is a major obstacle for large scale production. Here we report the engineering of an industrially friendly host, Saccharomyces cerevisiae, to produce BDO at high titer and yield. By inactivation of pyruvate decarboxylases (PDCs) followed by overexpression of MTH1 and adaptive evolution, the resultant yeast grew on glucose as the sole carbon source with ethanol production completely eliminated. Moreover, the pdc- strain consumed glucose and galactose simultaneously, which to our knowledge is unprecedented in S. cerevisiae strains. Subsequent introduction of a BDO biosynthetic pathway consisting of the cytosolic acetolactate synthase (cytoILV2), Bacillus subtilis acetolactate decarboxylase (BsAlsD), and the endogenous butanediol dehydrogenase (BDH1) resulted in the production of enantiopure (2R,3R)-butanediol (R-BDO). In shake flask fermentation, a yield over 70% of the theoretical value was achieved. Using fed-batch fermentation, more than 100g/L R-BDO (1100mM) was synthesized from a mixture of glucose and galactose, two major carbohydrate components in red algae. The high titer and yield of the enantiopure R-BDO produced as well as the ability to co-ferment glucose and galactose make our engineered yeast strain a superior host for cost-effective production of bio-based BDO from renewable resources.

KEYWORDS:

(2R,3R)-Butanediol; Glucose derepression; Metabolic engineering; Pyruvate decarboxylase; Sugar co-utilization

PMID:
24525332
DOI:
10.1016/j.ymben.2014.02.003
[Indexed for MEDLINE]

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