Microorganism strains for the production of 2.3-butanediol

A recombinant yeast having a reduced pyruvate decarboxylase activity, in the genome of which has been inserted:

• one or more nucleic acids encoding an acetolactate synthase or ALS,
• one or more nucleic acids encoding an acetolactate decarboxylase or ALD,
• one or more nucleic acids encoding a butanediol dehydrogenase or BDH, and
• two or more copies of nucleic acids encoding a NADH oxidase or NOXE,
• wherein the nucleic acid(s) encoding the acetolactate synthase or ALS is/are nucleic acid(s) selected from the group consisting of sequences having at least 65% nucleic acid identity with the nucleic acid sequences SEQ ID NO:
• 1, 3 and 5,
• wherein the nucleic acid(s) encoding the acetolactate decarboxylase or ALD is/are nucleic acid(s) selected from the group consisting of sequences having at least 36% nucleic acid identity with the nucleic acid sequences SEQ ID NO:
• 7, 9 and 11,
• wherein the nucleic acid(s) encoding the butanediol dehydrogenase or BDH is/are nucleic acid(s) selected from the group consisting of sequences having at least 63% nucleic acid identity with the nucleic acid sequences SEQ ID NO:
• 13, 15, 17 and 19, and
• wherein the nucleic acid(s) encoding the NADH oxidase or NOXE is/are nucleic acid(s) selected from the group consisting of sequences having at least 80% nucleic acid identity with the nucleic acid sequences SEQ ID NO:
• 21, 23, 25 and 27.