title: Improving biobutanol production in engineered Saccharomyces cerevisiae by manipulation of acetyl-CoA metabolism.
abstract: Recently, butanols (1-butanol, 2-butanol and iso-butanol) have generated attention as alternative gasoline additives. Butanols have several properties favorable in comparison to ethanol, and strong interest therefore exists in the reconstruction of the 1-butanol pathway in commonly used industrial microorganisms. In the present study, the biosynthetic pathway for 1-butanol production was reconstructed in the yeast Saccharomyces cerevisiae. In addition to introducing heterologous enzymes for butanol production, we engineered yeast to have increased flux toward cytosolic acetyl-CoA, the precursor metabolite for 1-butanol biosynthesis. This was done through introduction of a plasmid-containing genes for alcohol dehydrogenase (ADH2), acetaldehyde dehydrogenase (ALD6), acetyl-CoA synthetase (ACS), and acetyl-CoA acetyltransferase (ERG10), as well as the use of strains containing deletions in the malate synthase (MLS1) or citrate synthase (CIT2) genes. Our results show a trend to increased butanol production in strains engineered for increased cytosolic acetyl-CoA levels, with the best-producing strains having maximal butanol titers of 16.3 mg/l. This represents a 6.5-fold improvement in butanol titers compared to previous values reported for yeast and demonstrates the importance of an improved cytosolic acetyl-CoA supply for heterologous butanol production by this organism.
authors.affiliation: Systems and Synthetic Biology Group, Department of Chemical and Biological Engineering, Chalmers University of Technology, 41296, Gothenburg, Sweden.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Krivoruchko
authors.forename: Cristina
authors.initials: C
authors.lastname: Serrano-Amatriain
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
authors.forename: Verena
authors.initials: V
authors.lastname: Siewers
authors.forename: Jens
authors.initials: J
authors.lastname: Nielsen
mesh_terms: D020001:1-Butanol / Q000378:metabolism*; D000106:Acetate-CoA Ligase / Q000235:genetics / Q000378:metabolism; D000105:Acetyl Coenzyme A / Q000378:metabolism*; D000101:Acetyl-CoA C-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D000426:Alcohol Dehydrogenase / Q000235:genetics / Q000378:metabolism; D000445:Aldehyde Oxidoreductases / Q000235:genetics / Q000378:metabolism; D056804:Biofuels / Q000600:supply & distribution*; D053898:Biosynthetic Pathways / Q000235:genetics; D002950:Citrate (si)-Synthase / Q000235:genetics; D003600:Cytosol / Q000378:metabolism; D008292:Malate Synthase / Q000235:genetics; D060847:Metabolic Engineering; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D058615:Synthetic Biology
chemical_list: D056804:Biofuels; D029701:Saccharomyces cerevisiae Proteins; D000105:Acetyl Coenzyme A; D020001:1-Butanol; C509911:ADH2 protein, S cerevisiae; D000426:Alcohol Dehydrogenase; D000445:Aldehyde Oxidoreductases; C018699:aldehyde dehydrogenase (NAD(P)+); D000101:Acetyl-CoA C-Acetyltransferase; D002950:Citrate (si)-Synthase; D008292:Malate Synthase; D000106:Acetate-CoA Ligase