A method for enzymatic preparation of fludarabine phosphate, comprising reaction of fludarabine with a high-energy phosphate compound under the action of deoxyribonucleic acid kinase. According to said method, acetate kinase and acetyl phosphate free acid or acetyl phosphate are also added. The technical problems present in the existing processes are successfully addressed by employing the enzymatic process to prepare the fludarabine phosphate. The usage of the high-energy phosphate compound is reduced by means of adding acetate kinase to recycle and regenerate a small amount of the high-energy phosphate compound, thereby reducing the generation of by-products having similar structures to the fludarabine phosphate, enhancing the operation convenience of purification steps in the industrial production of the fludarabine phosphate. The process is environment friendly, the reaction conditions are moderate, the cost is low, and the yield and the purity of the product obtained are high.

The invention relates to a recombinant cell, preferably a yeast cell comprising: a) one or more heterologous genes encoding a glycerol dehydrogenase activity; b) one or more genes encoding a dihydroxyacetone kinase (E.C. 2.7.1.28 and/or E.C. 2.7.1.29); c) one or more heterologous genes encoding a ribulose-1,5-biphosphate carboxylase oxygenase (EC 4.1.1.39, RuBisCO); and d) one or more heterologous genes encoding a phosphoribulokinase (EC 2.7.1.19, PRK); and optionally e) one or more heterologous genes encoding for a glycerol transporter, wherein the recombinant yeast comprises overexpression of one or more PPP-genes. This cell can be used for the production of ethanol and advantageously produces little or no glycerol.

The present invention relates to a yeast cell that is genetically modified comprising: a) a disruption of one or more aldehyde dehydrogenase (E.C: 1.2.1.4) native to the yeast; b) one or more nucleotide sequence encoding a heterologous NAD+-dependent acetylating acetaldehyde dehydrogenase (E.C. 1.2.1.10); c) one or more nucleotide sequence encoding a homologous or heterologous acetyl-CoA synthetase (E.C. 6.2.1.1); and d) a modification that leads to reduction of glycerol 3-phosphate phosphohydrolase (E.C. 3.1.3.21) and/or glycerol 3-phosphate dehydrogenase (E.C. 1.1.1.8 or E.C. 1.1.5.3) activity, native to the yeast.

A method for enzymatic preparation of fludarabine phosphate, comprising reaction of fludarabine with a high-energy phosphate compound under the action of deoxyribonucleic acid kinase. According to said method, acetate kinase and acetyl phosphate free acid or acetyl phosphate are also added. The technical problems present in the existing processes are successfully addressed by employing the enzymatic process to prepare the fludarabine phosphate. The usage of the high-energy phosphate compound is reduced by means of adding acetate kinase to recycle and regenerate a small amount of the high-energy phosphate compound, thereby reducing the generation of by-products having similar structures to the fludarabine phosphate, enhancing the operation convenience of purification steps in the industrial production of the fludarabine phosphate. The process is environment friendly, the reaction conditions are moderate, the cost is low, and the yield and the purity of the product obtained are high.

The invention relates to a recombinant cell, preferably a yeast cell comprising: a) one or more heterologous genes encoding a glycerol dehydrogenase activity; b) one or more genes encoding a dihydroxyacetone kinase (E.C. 2.7.1.28 and/or E.C. 2.7.1.29); c) one or more heterologous genes encoding a ribulose-1,5-biphosphate carboxylase oxygenase (EC 4.1.1.39, RuBisCO); and d) one or more heterologous genes encoding a phosphoribulokinase (EC 2.7.1.19, PRK); and optionally e) one or more heterologous genes encoding for a glycerol transporter. This cell can be used for the production of ethanol and advantageously produces little or no glycerol.

The invention relates to a process for producing a fermentation product that comprises fermentation of a carbon source in a reactor with a cell, capable of converting sugar, glycerol and acetic acid, wherein the carbon source comprises sugar and acetic acid, comprising the following steps: a) Inoculating a optionally diluted carbon source with the cell; b) optionally fermenting the reactor in batch mode; c) adding carbon source comprising glycerol and optionally sugar gradually to the reactor; d) after sufficient fermentation time, isolation of fermentation product from the reactor, e) optionally keeping the remaining fraction after isolation of step d) as spent broth; and f) optionally using the spent broth in step a) to dilute the carbon source.

The invention relates to a process for producing a fermentation product that comprises fermentation of a carbon source in a reactor with a cell, capable of converting sugar, glycerol and acetic acid, wherein the carbon source comprises sugar and acetic acid, comprising the following steps: a) Inoculating a optionally diluted carbon source with the cell; b) optionally fermenting the reactor in batch mode; c) adding carbon source comprising glycerol and optionally sugar gradually to the reactor; d) after sufficient fermentation time, isolation of fermentation product from the reactor, e) optionally keeping the remaining fraction after isolation of step d) as spent broth; and f) optionally using the spent broth in step a) to dilute the carbon source.

The invention relates to a recombinant cell, preferably a yeast cell comprising one or more genes coding for an enzyme having glycerol dehydrogenase activity, one or more genes coding dihydroxyacetone kinase (E.C. 2.7.1.28 and/or E.C. 2.7.1.29); one or more genes coding for an enzyme in an acetyl-CoA-production pathway and one or more genes coding for an enzyme having at least NAD.sup.+ dependent acetylating acetaldehyde dehydrogenase activity (EC 1.2.1.10 or EC 1.1.1.2), and optionally one or more genes coding for a glycerol transporter. This cell can be used for the production of ethanol and advantageously produces little or no glycerol.

Cell that is genetically modified comprising: a) one or more nucleotide sequence encoding a NAD.sub.+-dependent acetylating acetaldehyde dehydrogenase (E.C. 1.2.1.10); b) one or more nucleotide sequence encoding a acetyl-CoA synthetase (E.C. 6.2.1.1); c) one or more nucleotide sequence encoding a glycerol dehydrogenase (E.C. 1.1.1.6); and d) one or more nucleotide sequence encoding a dihydroxyacetone kinase (E.C. 2.7.1.28 or E.C. 2.7.1.29).

Cell that is genetically modified comprising: a) one or more nucleotide sequence encoding a NAD+-dependent acetylating acetaldehyde dehydrogenase (E.C. 1.2.1.10); b) one or more nucleotide sequence encoding a acetyl-CoA synthetase (E.C. 6.2.1.1); c) one or more nucleotide sequence encoding a glycerol dehydrogenase (E.C. 1.1.1.6); and d) one or more nucleotide sequence encoding a dihydroxyacetone kinase (E.C. 2.7.1.28 or E.C. 2.7.1.29).