Fermentative glycerol-free ethanol production

A transgenic yeast cell comprising one or more recombinant heterologous, nucleic acid sequences encoding an NAD+-dependent acetylating acetaldehyde dehydrogenase (EC 1.2.1.10),nwherein said cell lacks enzymatic activity needed for the NADH-dependent glycerol synthesis, or said cell has a reduced enzymatic activity with respect to the NADH-dependent glycerol synthesis compared to a corresponding wild-type yeast cell; andwherein at least one said NAD+-dependent acetylating acetaldehyde dehydrogenase is represented by SEQ ID NO:2 or by SEQ ID:29 or a functional homolog of SEQ ID NO:2 or SEQ ID NO:29,wherein said functional homolog has a sequence identity of at least 90% with SEQ ID NO:2 or SEQ ID NO:29,wherein said cell comprises one or more nucleic acid sequences encoding an acetyl-Coenzyme A synthetase activity (EC 6.2.1.1) and one or more nucleic acid sequences encoding NAD+-dependent alcohol dehydrogenase activity (EC 1.1.1.1) andwherein the molar ratio of acetate to carbohydrate consumed by anaerobic growth of said yeast cell is at least 0.004.

A vector for the functional expression of a nucleotide sequence encoding a polypeptide having enzymatic activity for converting acetyl-Coenzyme A into acetaldehyde in the cytosol of said yeast cell comprising said sequence operably linked to a promoter functional in the yeast cell, wherein said polypeptide comprises a sequence according to SEQ ID NO: 2, SEQ ID NO: 29, or a functional homolog of said sequences, wherein said functional homolog has a sequence identity of at least 90% with SEQ ID NO: 2 or SEQ ID NO: 29.