title: Improved production of isoamyl acetate by a sake yeast mutant resistant to an isoprenoid analog and its dependence on alcohol acetyltransferase activity, but not on isoamyl alcohol production.
abstract: 1-Farnesylpyridinium (FPy), an analog of isoprenoid farnesol, strongly inhibited the growth of sake yeast at 120 microM in YPD medium, whereas at 30 microM it reduced cellular production of isoamyl acetate to 20% of the control level despite the absence of inhibitory effect on CO2 evolution. The FPy-resistant mutant A1 was characterized by the high production of flavor compounds represented by a nearly threefold increase in the level of isoamyl acetate in YPD medium in which the level of isoamyl alcohol as its precursor remained almost unchanged. The FPy resistance phenotype of strain A1 was not accompanied by cellular resistance to either the L-leucine analog or L-canavanine, which alters yeast amino acid metabolism in favor of isoamyl alcohol production. Alcohol acetyltransferase (AATase) activity was high in strain A1, which further increased in response to isoamyl alcohol accumulation in medium. Flavor compound production in sake brewing could be improved using strain A1, resulting in a 1.4-fold increase in isoamyl acetate production in spite of a limited production of isoamyl alcohol.
authors.affiliation: Industrial Technology Center, Kyoto Municipal Industrial Research Institute, 134 Chudoji Minami-machi, Shimogyo-ku, Kyoto 600-8813, Japan. h-kiyoo@city.kyoto.jp
authors.forename: Kiyoo
authors.initials: K
authors.lastname: Hirooka
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Nobuo
authors.initials: N
authors.lastname: Tsutsui
authors.forename: Toshio
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D025141:Drug Resistance, Fungal / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation; D000439:Pentanols / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D011726:Pyridinium Compounds / Q000008:administration & dosage*; D012441:Saccharomyces cerevisiae / Q000145:classification / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D012717:Sesquiterpenes / Q000008:administration & dosage*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013045:Species Specificity; D013729:Terpenes / Q000008:administration & dosage
chemical_list: D000439:Pentanols; D011506:Proteins; D011726:Pyridinium Compounds; D012717:Sesquiterpenes; D013729:Terpenes; C453495:farnesylpyridinium; C029683:isopentyl alcohol; C079238:alcohol O-acetyltransferase; C020377:isoamyl acetate