Yeast strains for saccharide fermentation

A transformed yeast comprising a DNA construct substantially free of prokaryotic DNA, said DNA construct comprising at least one of the following genes:

• maltase, maltose permease or a MAL regulator protein wherein said gene(s) are capable of expression in said yeast;
• said parent yeast having a corresponding gene encoding a protein having the same function as that of the protein encoded by said gene;
• wherein said transformed yeast has an increased rate of fermentation of maltose into ethanol and carbon dioxide when said DNA construct is expressed.

A method for producing a transformed yeast having an enhanced rate of sugar fermentation as compared to a parent yeast, said method comprising:

• introducing into said parent yeast at least one DNA construct which comprises at least one gene encoding a protein promoting at least one of the uptake of a sugar substrate and initial metabolic conversion of a sugar substrate subsequent to uptake, the gene or genes being expressed in said yeast and encoding a maltose permease, maltase, or a maltose regulatory protein,
• said parent yeast having a corresponding gene encoding a protein having the same function as that of the protein encoded by said gene.
• whereby said transformed yeast is produced.

A vector selected from the group consisting of

• pGb-RBRRO1,
• pGb-RBN3, and
• pGB-RBREGO1.

A yeast selected from the group consisting of

• Saccharomyces cerevisiae strain CpGb-eMAL61, and
• Saccharomyces cerevisiae strain ApGb-p2RBRR01#1.

A transformed yeast comprising a DNA construct substantially free of prokaryotic DNA, said DNA construct comprising at least one of the following genes;

• maltase, maltose permease or a maltose regulatory protein wherein said gene(s) are capable of expression in said yeast;
• the parent yeast which does not comprise said DNA construct having a corresponding gene encoding a protein having the same function as that of the protein encoded by said gene;
• wherein said transformed yeast has an increased rate of sugar fermentation as compared to said parent yeast.