Formation of β-Phenethyl Alcohol, Tyrosol, and Tryptophol from Some Sugars by Saccharomyces cerevisiae

Abstract

Formation of β-phenethyl alcohol and bitter compounds, tyrosol and tryptophol, from sucrose, glucose, or fructose by culturing Saccharomyces cerevisiae was examined.
Saccharomyces cerevisiae IAM 4274 was cultured in a synthetic medium containing glucose as sole carbon source and no aromatic amino acids. In an ether extract of the yeast culture, three metabolic products were found. Each product was isolated by silica gel column chromatography and identified as β-phenethyl alcohol, tyrosol, and tryptophol, respectively, with R_f values, color reactions with H₂SO₄, FeCl₃, Diazo reagent, and Iodine vapor on a TLC-plate, UV and IR absorption spectra, and melting point.
Furthermore, three strains of Saccharomyces cerevisiae were cultured in a synthetic medium containing sucrose, glucose, or fructose as sole carbon source.β-Phenethyl alcohol, tyrosol, and tryptophol in the culture liquid were determined by gas chromatography. All tested strains formed these compounds in all media, but the formation of tryptophol was smaller than that of β-phenethyl alcohol and tyrosol.β-Phenethyl alcohol and tyrosol were formed more in the glucose-and fructose-media than in the sucrosemedium.
Phenylalanine and tyrosine were found in the yeast culture liquid, suggesting that β-phenethyl alcohol and tyrosol might be formed respectively from phenylalanine and tyrosine biosynthesized from sugar by the yeast.