title: Metabolic engineering of Saccharomyces cerevisiae for the production of triacetic acid lactone.
abstract: Biobased chemicals have become attractive replacements for their fossil-fuel counterparts. Recent studies have shown triacetic acid lactone (TAL) to be a promising candidate, capable of undergoing chemical conversion to sorbic acid and other valuable intermediates. In this study, Saccharomyces cerevisiae was engineered for the high-level production of TAL by overexpression of the Gerbera hybrida 2-pyrone synthase (2-PS) and systematic engineering of the yeast metabolic pathways. Pathway analysis and a computational approach were employed to target increases in cofactor and precursor pools to improve TAL synthesis. The pathways engineered include those for energy storage and generation, pentose biosynthesis, gluconeogenesis, lipid biosynthesis and regulation, cofactor transport, and fermentative capacity. Seventeen genes were selected for disruption and independently screened for their effect on TAL production; combinations of knockouts were then evaluated. A combination of the pathway engineering and optimal culture parameters led to a 37-fold increase in titer to 2.2g/L and a 50-fold increase in yield to 0.13 (g/g glucose). These values are the highest reported in the literature, and provide a 3-fold improvement in yield over previous reports using S. cerevisiae. Identification of these metabolic bottlenecks provides a strategy for overproduction of other acetyl-CoA-dependent products in yeast.
authors.affiliation: Department of Chemical Engineering and Materials Science, University of California, Irvine, CA 92697-2575 USA.
authors.forename: Javier
authors.initials: J
authors.lastname: Cardenas
authors.affiliation: Department of Chemical Engineering and Materials Science, University of California, Irvine, CA 92697-2575 USA. Electronic address: ndasilva@uci.edu.
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Da Silva
mesh_terms: D061249:Batch Cell Culture Techniques / Q000379:methods*; D005947:Glucose / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D011753:Pyrones / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics
chemical_list: D011753:Pyrones; D029701:Saccharomyces cerevisiae Proteins; C030720:triacetic acid lactone; D005947:Glucose
keywords: 2-pyrone synthase; Biorenewable chemicals; Central carbon metabolism; Metabolic engineering; Saccharomyces cerevisiae; Triacetic acid lactone