The present invention provides a Saccharomyces uvarum strain capable of low production of higher alcohols and strong degradation of malic acid. After the wine using Saccharomyces uvarum recombinant strain of the present invention is fermented for 5 days, with other fermentation properties unaffected, the content of isobutanol, isoamyl alcohol and phenethyl alcohol in the wine is 28.18 mg/L, 171.76 mg/L and 13.60 mg/L respectively, which is reduced by 20.28%, 14.77% and 11.26% compared with the starting strain, the total content of main higher alcohols (n-propanol, isobutanol, isoamyl alcohol and phenethyl alcohol) is reduced by 12.97%, and the content of malic acid is reduced to 1.13 g/L after fermentation, which greatly shortens the fermentation period, overcomes the influence of lactic acid bacteria fermentation in the ordinary fermentation process and unpleasant flavor caused by higher content of higher alcohols.

A Saccharomyces cerevisiae strain with high yield of ethyl butyrate and a construction method and an application thereof are provided. The strain is obtained by over-expressing in the starting strain acetyl coenzyme A acyl transferase gene Erg10, 3-hydroxybutyryl coenzyme A dehydrogenase gene Hbd, 3-hydroxybutyryl coenzyme A dehydratase gene Crt, trans-2-enoyl coenzyme A reductase gene Ter, and alcohol acyl transferase gene AAT. Compared to the starting bacteria not producing ethyl butyrate, the yield of ethyl butyrate of the constructed strain reaches 77.33±3.79 mg/L, the yield of the ethyl butyrate of the strain with double copy expression of gene Ter and gene AAT reaches 99.65±7.32 mg/L, increased by 28.9% compared with the EST strain, and 40.93±3.18 mg/L of ethyl crotonate is unexpectedly produced.

The present invention relates to a yeast strain likely to be obtained by hybridizing a strain S1 with a strain S2, said yeast strain presenting, according to test A, the following characteristics: fermentation kinetics from 15 to 22 days at a temperature of 24° C.; and resistance with an alcoholic strength of more than or equal to 15% v/v; and a nitrogen requirement of less than or equal to 200 ppm,
to the method of producing this strain and to its use.

A Saccharomyces cerevisiae strain with high yield of ethyl butyrate and a construction method and an application thereof are provided. The strain is obtained by over-expressing in the starting strain acetyl coenzyme A acyl transferase gene Erg10, 3-hydroxybutyryl coenzyme A dehydrogenase gene Hbd, 3-hydroxybutyryl coenzyme A dehydratase gene Crt, trans-2-enoyl coenzyme A reductase gene Ter, and alcohol acyl transferase gene AAT. Compared to the starting bacteria not producing ethyl butyrate, the yield of ethyl butyrate of the constructed strain reaches 77.33±3.79 mg/L, the yield of the ethyl butyrate of the strain with double copy expression of gene Ter and gene AAT reaches 99.65±7.32 mg/L, increased by 28.9% compared with the EST strain, and 40.93±3.18 mg/L of ethyl crotonate is unexpectedly produced.

Provided herein are genetically modified yeast cells that recombinantly express a gene encoding an alcohol-O-acyltransferase (AAT) enzyme and a gene encoding a fatty acid synthase a subunit (FAS2) enzyme. Also provided are methods of producing fermented beverages and compositions comprising ethanol using the genetically modified yeast cells described herein.

Provided herein are genetically modified yeast cells that recombinantly expresses a gene encoding a mutant beta-lyase. Also provided are methods of producing fermented products and methods of producing ethanol.

The present invention relates to a yeast strain likely to be obtained by hybridizing a strain S1 with a strain S2, said yeast strain presenting, according to test A, the following characteristics: fermentation kinetics from 15 to 22 days at a temperature of 24? C.; and resistance with an alcoholic strength of more than or equal to 15% v/v; and a nitrogen requirement of less than or equal to 200 ppm,
to the method of producing this strain and to its use.

A method of producing yeast mutants and the use thereof. In order to provide yeasts which, at a given sugar content, produce a low ethanol content and a relatively high glycerol content in ethanolic fermentation and which are simultaneously obtainable rapidly, at least one yeast strain is contacted in a first mutagenesis step with a first mutagen and in a second mutagenesis step with a second mutagen. The first and second mutagens are different from one another and are selected from the following groups: nucleotide-alkylating agent, nucleotide-deaminating agent, and UV radiation. The method further includes a first selection step executed between the first and second mutagenesis steps and a second selection step being executed after the second mutagenesis step, in which the mutants that originate from the prior mutagenesis step in each case are exposed to a selection factor selected from the following groups: (a) hypertonic medium and (b) alcohol dehydrogenase inhibitor.

Provided herein are genetically modified yeast cells that recombinantly express a glycosidase enzyme. Provided herein are genetically modified yeast cells that recombinantly express a glycosidase enzyme and/or an O-methyltransferase enzyme. Also provided are methods of producing fermented beverages and compositions comprising ethanol using the genetically modified yeast cells described herein.

The present invention relates to the identification of alleles of the MET2 and SKP2 genes having the effect of reducing the production of sulphites, of hydrogen sulphide and of acetaldehyde by Saccharomyces, and to the use of these alleles in methods for controlling the production of these compounds during alcoholic fermentation.