The present invention relates to processes for producing ethanol from lignocellulosic hydrolysates comprising hexoses, pentoses and acetic acid, whereby genetically modified yeast cells are use that comprise an exogenous gene encoding an acetaldehyde dehydrogenase and a bacterial gene encoding an enzyme with NAD.sup.+-linked glycerol dehydrogenase activity. The process is further characterized in that glycerol is present in or fed into the culture medium, whereby the modified yeast cell ferments the hexoses, pentoses, acetic acid and glycerol to ethanol. The invention further relates to yeast cells for use in such processes. The yeast cells advantageously comprise genetic modifications that improve glycerol utilization such as modifications that increase one or more of dihydroxyacetone kinase activity and transport of glycerol into the cell. The yeast cell further preferably comprises a functional exogenous xylose isomerase gene and/or functional exogenous genes which confer to the cell the ability to convert L-arabinose into D-xylulose 5-phosphate and they may comprise a genetic modification that increase acetyl-CoA synthetase activity.

A process for the production of ethanol. comprising: fermentation of a feed. under anaerobic conditions. wherein the feed contains a di-saccharide. oligo-saccharide and/or poly-saccharide and wherein the fermentation is carried out in the presence of a recombinant yeast cell. which recombinant yeast produces a combination of proteins having glucosidase activity: and recovery of ethanol. and a recombinant yeast cell for use therein.

A recombinant yeast cell functionally expressing: a) a nucleic acid sequence encoding a protein having NAD+-dependent acetylating acetaldehyde dehydrogenase activity (EC 1.2.1.10); and b) a nucleic acid sequence encoding a protein having transketolase activity (EC 2.2.1.1), wherein the expression of the nucleic acid sequence encoding the protein having transketolase activity is under control of a promoter (the TKL promoter), which TKL promoter has an anaerobic/aerobic expression ratio for the transketolase of 2 or more.

Recombinant strains are obtained for the production of allulose, allose, and allitol by regulating intracellular glucose metabolism, reducing the enzyme activity of fructose 6-phosphate kinase, and enhancing the enzyme activities of glucokinase and glucose-6-phosphate isomerase, allulose 6-phosphate 3-epimerase, allulose 6-phosphate phosphatase, fructose permease and fructokinase, and optionally enhancing the enzyme activities of ribose 5-phosphate isomerase, allose 6-phosphate phosphatase, ribitol dehydrogenase, glycerol permease, glycerol dehydrogenase, and dihydroxyacetone kinase. A method for producing allulose and allose is an extracellular multienzyme cascade method. Multienzyme cascade catalysis and fermentation are coupled to improve the conversion rate of starch sugar or sucrose to the synthesized allulose.

A recombinant yeast cell comprising a nucleotide sequence encoding a protein, which protein comprises an amino acid sequence of SEQ ID NO: 01 or an amino acid sequence which has at least 90% sequence identity, preferably at least 95%, 98%, or 99% sequence identity with the amino acid sequence of SEQ ID NO: 01.

A recombinant yeast cell functionally expressing: a) a heterologous nucleic acid sequence encoding a protein having ribulose-1,5-phosphate carboxylase/oxygenase activity (EC4.1.1.39; Rubisco), a heterologous nucleic acid sequence encoding a protein having phosphoribulokinase activity (EC2.7.1.19; PRK) and optionally one or more nucleic acid sequences encoding for molecular chaperones for the protein having ribulose-1,5-phosphate carboxylase/oxygenase activity; and b) a nucleic acid sequence encoding a protein having transketolase activity (EC 2.2.1.1), wherein the expression of the nucleic acid sequence encoding the protein having transketolase activity is under control of a promoter (the TKL promoter), which TKL promoter has an anaerobic/aerobic expression ratio for the transketolase of 2 or more.

A recombinant yeast cell functionally expressing: a nucleic acid sequence encoding a native protein having transketolase activity (EC 2.2.1.1); and a nucleic acid sequence encoding a heterologous protein having transketolase activity (EC 2.2.1.1).

A recombinant yeast cell functionally expressing: a) a nucleic acid sequence encoding a protein comprising phospho-ketolase (PKL) activity (EC 4.1.2.9 or EC 4.1.2.22) and/or a nucleic acid sequence encoding a protein having phosphotransacetylase (PTA) activity (EC 2.3.1.8) and/or a nucleic acid sequence encoding a protein having acetate kinase (ACK) activity (EC 2.7.2.12); and/or) a nucleic acid sequence encoding a protein having transketolase activity (EC 2.2.1.1), wherein the expression of the nucleic acid sequence encoding the protein having transketolase activity is under control of a promoter (the TKL promoter), which TKL promoter has an anaerobic/aerobic expression ratio for the transketolase of (2) or more.

A recombinant yeast cell functionally expressing: a) a nucleic acid sequence encoding an enzyme having NADH-dependent nitrate reductase activity and/or a nucleic acid sequence encoding an enzyme having NADH-dependent nitrite reductase activity; and b) a nucleic acid sequence encoding a protein having transketolase activity (EC 2.2.1.1), wherein the expression of the nucleic acid sequence encoding the protein having transketolase activity is under control of a promoter (the TKL promoter), which TKL promoter has an anaerobic/aerobic expression ratio for the transketolase of 2 or more.

The present specification relates to a microorganism into which a GPD gene, a GPP gene, and dhaB, gdrAB, aldH and/or yqhD genes are introduced, and/or use thereof, the microorganism being capable of simultaneously producing 1,3-PDO and 3-HP.