A bacterial cell factory for efficient production of ethanol from whey

Use of a genetically engineered lactic acid bacterium for the production of ethanol from an aqueous culture medium comprising

• I. whey premeate or residual whey permeate, and
• II. an amino nitrogen source;
• wherein the genetically engineered lactic acid bacterium comprises transgenes encoding:
• i. a polypeptide having pyruvate decarboxylase (PDC) activity (EC 4.1.1.1);
• and
• ii. a polypeptide having alcohol dehydrogenase B activity (EC 1.1.1.1);
• and
• wherein the genome of said lactic acid bacterium comprises genes encoding polypeptides having:
• iii. lactose-specific phosphotransferase system (PTS) activity (EC 2.7.1.69)
• iv. phospho-β-D-galactosidase activity (EC 3.2.1.85)
• v. galactose-6-phosphate isomerase activity (EC 5.3.1.26),
• vi. D-tagatose-6-phosphate kinase activity (EC 2.7.1.114), and
• vii. tagatose 1,6-diphosphate aldolase activity (EC 4.1.2.40);
• and
• wherein the genome of said lactic acid bacterium is deleted for genes or lacks functional genes encoding polypeptides having an enzymatic activity of:
• viii. lactate dehydrogenase (E.C 1.1.1.27 or E.C. 1.1.1.28)
• ix. phosphotransacetylase (E.C. 2.3.1.8) and
• x. bifunctional alcohol dehydrogenase (E.C. 1.1.1.1 and EC 1.2.1.10).

A genetically engineered lactic acid bacterium for the production of ethanol from an aqueous culture medium comprising whey permeate or residual whey permeate, and an amino nitrogen source;

• wherein the genetically engineered lactic acid bacterium comprises transgenes encoding:
• i. a polypeptide having pyruvate decarboxylase (PDC) activity (EC 4.1.1.1);
• and
• ii. a polypeptide having alcohol dehydrogenase B activity (EC 1.1.1.1);
• and
• wherein the genome of said lactic acid bacterium comprises genes encoding polypeptides having:
• iii. lactose-specific phosphotransferase system (PTS) activity (EC 2.7.1.69)
• iv. phospho-β-D-galactosidase activity (EC 3.2.1.85)
• v. galactose-6-phosphate isomerase activity (EC 5.3.1.26),
• vi. D-tagatose-6-phosphate kinase activity (EC 2.7.1.114), and
• vii. tagatose 1,6-diphosphate aldolase activity (EC 4.1.2.40);
• and
• wherein the genome of said lactic acid bacterium is deleted for genes or lacks functional genes or genes encoding polypeptides having an enzymatic activity of:
• viii. lactate dehydrogenase (E.C 1.1.1.27 or E.C. 1.1.1.28)
• ix. phosphotransacetylase (E.C. 2.3.1.8) and
• x. bifunctional alcohol dehydrogenase (E.C. 1.1.1.1 and EC 1.2.1.10).