Compositions and methods for reducing h2s levels in fermented beverages

An expression vector comprising a polynucleotide encoding a MET10 polypeptide that does not catalyze the conversion of sulfite into sulfide, wherein the amino acid at position 662 of the MET10 polypeptide is not threonine, and wherein the polynucleotide is operably linked to an expression control sequence.

An improved yeast cell that does not produce hydrogen sulfide comprising an exogenous polynucleotide encoding a MET10 polypeptide that does not catalyze the conversion of sulfite to sulfide, wherein the amino acid at position 662 of the MET10 polypeptide is not threonine, wherein a parent cell of the improved yeast cell produces hydrogen sulfide.

An improved yeast cell culture that produces reduced levels of hydrogen sulfide comprising a population of yeast cells, the yeast cells comprising an exogenous polynucleotide encoding a MET10 polypeptide that does not catalyze the conversion of sulfite to sulfide, wherein the amino acid at position 662 of the MET10 polypeptide is not threonine, wherein the improved yeast cell culture produces reduced hydrogen sulfide in comparison to a culture of parent cells.

A method of producing an improved yeast cell that produces reduced levels of hydrogen sulfide, the method comprising replacing an endogenous polynucleotide encoding a sulfide active MET10 polypeptide with a polynucleotide encoding a sulfide inactive MET10 polypeptide by introducing into a parent of the yeast cell a polynucleotide encoding a sulfide inactive MET10 polypeptide that does not catalyze the conversion of sulfite to sulfide, wherein the amino acid at position 662 of the sulfide inactive MET10 polypeptide is not threonine, wherein the parent of the improved yeast cell produces hydrogen sulfide.

An isolated polynucleotide capable of distinguishing between the sequences provided in SEQ ID NO:1 or a complement thereof and a nucleic acid encoding a wild type MET10.