(615d) Utilizing an Endogenous Pathway for 1-Butanol Production in Saccharomyces Cerevisiae

Authors: 
Si, T., University of Illinois at Urbana Champaign
Luo, Y., University of Illinois at Urbana-Champaign
Xiao, H., University of Illinois at Urbana Champaign
Zhao, H., University of Illinois at Urbana Champaign

Microbial production of higher alcohols from renewable feedstock has attracted intensive attention owing to its potential as a source for next-generation gasoline substitutes. Here we report the discovery, characterization and engineering of an endogenous 1-butanol pathway in Saccharomyces cerevisiae. Upon introduction of a single gene deletion adh1Δ, S. cerevisiae was able to accumulate more than 120 mg/L 1-butanol from glucose in rich medium. Precursor feeding, 13C-isotope labeling and gene deletion experiments demonstrated that the endogenous 1-butanol production was dependent on catabolism of threonine in a manner similar to fusel alcohol production by the Ehrlich pathway. Specifically, the leucine biosynthesis pathway was engaged in the conversion of key 2-keto acid intermediates. Overexpression of the pathway enzymes and elimination of competing pathways achieved the highest reported 1-butanol titer in S. cerevisiae (243 mg/L).