The invention relates to a process for the production of ethanol, the process comprising fermenting of a carbon source composition with a recombinant yeast,

wherein the carbon source composition comprises at least glucose and arabinose; and
wherein the recombinant yeast comprises arabinose isomerase activity, ribulokinase activity, ribulose phosphate epimerase activity, glycerol uptake activity and glycerol conversion capacity; and
wherein the recombinant yeast further comprises a genetic modification leading to the reduction, downregulation, inhibition and/or elimination of the activity of a homologous protein with glycerol-efflux activity; and
wherein each of the glucose and the arabinose is converted into ethanol.

In addition, the invention relates to a recombinant yeast that can be used in such a process.

The present invention relates to polypeptides which are Gal2 variants comprising at least one amino acid substitution at a position corresponding to T354, and optionally further amino acid substitution(s). The present invention further relates to nucleic acid molecules encoding the polypeptides and to host cells containing said nucleic acid molecules. The present invention further relates to a method for the production of bioethanol and/or other bio-based compounds, comprising the expression of said nucleic acid molecules, preferably in said host cells. The present invention also relates to the use of the polypeptides, nucleic acids molecule or host cells for the production of bioethanol and/or other bio-based compounds, and/or for the recombinant fermentation of biomaterial containing pentose(s), preferably D-xylose and/or L-arabinose.

The invention relates to a method for preparing a yeast which is capable of simultaneously fermenting a pentose and a hexose sugar, the method comprising providing a yeast which comprises: one or more heterologous genes encoding an enzyme of a pentose metabolic pathway, a disruption of a gene encoding a ribulose-phosphate 3-epimerase and a disruption of a gene encoding a glucose-6-phosphate isomerase, and one or more overexpressed endogenous genes encoding an enzyme of the pentose phosphate pathway; and subjecting the yeast to evolutionary engineering on a medium comprising a hexose sugar and at least one pentose sugar, selecting for a yeast with improved growth rate when grown on a media comprising a hexose and at least one pentose sugar, so as to obtain an evolved yeast.

Provided are excellent L-arabinose metabolic genes that function in yeasts. Provided is an L-arabinose metabolic gene cluster including an L-arabinose isomerase gene specified by a predetermined SEQ ID, an L-ribulokinase gene specified by a predetermined SEQ ID, and an L-ribulose-5-phosphate-4-epimerase gene specified by a predetermined SEQ ID.

A method for preparing a yeast capable of simultaneously fermenting a pentose and a hexose sugar, comprising: (a) providing a yeast comprising: one or more heterologous genes encoding an enzyme of a pentose metabolic pathway; disruptions of a gene encoding a ribulose-phosphate 3-epimerase and of a gene encoding a glucose-6-phosphate isomerase; one or more overexpressed endogenous genes encoding an enzyme of the pentose phosphate pathway; and a disruption of one or more genes encoding an NADPH dependent 6-phosphogluconate dehydrogenase, (b) subjecting said yeast to evolutionary engineering on a medium comprising a hexose sugar and at least one pentose sugar, selecting for a yeast with improved growth rate obtain an evolved yeast; (d) restoring, in the evolved yeast, one or more of the disrupted genes, or: (d) identifying genetic permutations in at least part of the genome of the evolved yeast by genome sequencing; (e) constructing an improved pentose and hexose-fermenting yeast comprising one or more said genetic permutations. Also described is a recombinant yeast comprising one or more heterologous genes of a pentose metabolic pathway, and a gene encoding a variant of a parent polypeptide, the variant comprising an amino acid sequence comprising at least one mutation, when aligned with the amino acid sequence in SEQ ID NO: 6.

The present invention relates to a new L-arabinose assimilation pathway and uses thereof. In particular, the present invention relates to polypeptides exhibiting L-arabinose isomerase, L-ribulokinase or L-ribulose-5-phosphate-4-epimerase activity, and recombinant host cells expressing said polypeptides. The present invention also relates to a method of producing a fermentation product, preferably ethanol, from an arabinose containing substrate, using a polypeptide or a host cell of the invention.

The present invention relates to polypeptides which are Gal2 variants comprising at least one amino acid substitution at a position corresponding to M435, and optionally further amino acid substitution(s). The present invention further relates to nucleic acid molecules encoding the polypeptides and to host cells containing said nucleic acid molecules. The present invention further relates to a method for the production of bioethanol and/or other bio-based compounds, comprising the expression of said nucleic acid molecules, preferably in said host cells. The present invention also relates to the use of the polypeptides, nucleic acids molecule or host cells for the production of bioethanol and/or other bio-based compounds, and/or for the recombinant fermentation of biomaterial containing pentose(s), preferably D-xylose and/or L-arabinose.

The present invention relates to polypeptides which are Gal2 variants comprising at least one amino acid substitution at a position corresponding to T354, and optionally further amino acid substitution(s). The present invention further relates to nucleic acid molecules encoding the polypeptides and to host cells containing said nucleic acid molecules. The present invention further relates to a method for the production of bioethanol and/or other bio-based compounds, comprising the expression of said nucleic acid molecules, preferably in said host cells. The present invention also relates to the use of the polypeptides, nucleic acids molecule or host cells for the production of bioethanol and/or other bio-based compounds, and/or for the recombinant fermentation of biomaterial containing pentose(s), preferably D-xylose and/or L-arabinose.

The invention relates to recombinant cells and their use in the production of ethylene glycol.

The present invention relates to a new L-arabinose assimilation pathway and uses thereof. In particular, the present invention relates to polypeptides exhibiting L-arabinose isomerase, L-ribulokinase or L-ribulose-5-phosphate-4-epimerase activity, and recombinant host cells expressing said polypeptides. The present invention also relates to a method of producing a fermentation product, preferably ethanol, from an arabinose containing substrate, using a polypeptide or a host cell of the invention.