The invention relates to an alcoholic fermentation process in the presence of one or more high alcohol tolerant yeast and one or more maltotriose positive yeast. The process of the present invention can be a fermentation process for the production of ethanol, for the production of beer, for the production of wine and the like. in a preferred embodiment, the present invention relates to a process for the production of ethanol in the presence of distiller's yeast and baker's yeast.

The invention relates to an alcoholic fermentation process in the presence of one or more high alcohol tolerant yeast and one or more maltotriose positive yeast. The process of the present invention can be a fermentation process for the production of ethanol, for the production of beer, for the production of wine and the like. in a preferred embodiment, the present invention relates to a process for the production of ethanol in the presence of distiller's yeast and baker's yeast.

A process for producing ethanol from lactose containing substrates, comprising simultaneously saccharifying the substrate to produce monosaccharide and fermenting the monosaccharide to produce ethanol at a pH from 3.5-5.5, using a fermenting organism, wherein saccharification is carried out in the presence of a lactase, and wherein the fermenting organism is a Saccharomyces sp., and the ratio between the incubation time required for obtaining at least 90% hydrolysis of the lactose present in the substrate (t-.sub.1) and the total fermentation time (t.sub.2) is in the range of 0.1 to 1, and the Saccharomyces sp. is added in amounts that will result in an ethanol yield of at least 70% w/w of the theoretical ethanol yield from lactose by the end of fermentation.

A process for producing ethanol from lactose containing substrates, comprising simultaneously saccharifying the substrate to produce monosaccharide and fermenting the monosaccharide to produce ethanol at a pH from 3.5-5.5, using a fermenting organism, wherein saccharification is carried out in the presence of a lactase, and wherein the fermenting organism is a Saccharomyces sp., and the ratio between the incubation time required for obtaining at least 90% hydrolysis of the lactose present in the substrate (t-.sub.1) and the total fermentation time (t.sub.2) is in the range of 0.1 to 1, and the Saccharomyces sp. is added in amounts that will result in an ethanol yield of at least 70% w/w of the theoretical ethanol yield from lactose by the end of fermentation.

Provided herein is a process for hydrolyzing a cellulosic feedstock to produce sugar. The process comprises introducing a pretreated cellulosic slurry to an inlet region of a plug flow hydrolysis reactor using a slurry introduction device that reduces the axial momentum of the slurry at the surface of the reactor contents. The cellulosic feedstock slurry is hydrolyzed in the plug flow hydrolysis reactor by contacting the cellulosic feedstock with at least cellulase enzymes to produce glucose. Also provided herein is a vertically-oriented, unmixed downflow hydrolysis reactor for hydrolyzing a pretreated cellulosic feedstock slurry which comprises such a slurry introduction device disposed in a top region thereof.

Provided herein is a process for hydrolyzing a cellulosic feedstock to produce sugar. The process comprises introducing a pretreated cellulosic slurry to an inlet region of a plug flow hydrolysis reactor using a slurry introduction device that reduces the axial momentum of the slurry at the surface of the reactor contents. The cellulosic feedstock slurry is hydrolyzed in the plug flow hydrolysis reactor by contacting the cellulosic feedstock with at least cellulase enzymes to produce glucose. Also provided herein is a vertically-oriented, unmixed downflow hydrolysis reactor for hydrolyzing a pretreated cellulosic feedstock slurry which comprises such a slurry introduction device disposed in a top region thereof.

Methods of and system for growing and maintaining an optimized/ideal active yeast solution in the yeast tank and fermenter tank during the fermentation filling cycle are provided. A new yeast stage tank is used between the yeast tank and the fermenter tank allowing yeast to rapidly produce a huge amount of active young yeast cells for a fermenter during the filling period. A measurable and useful controlling factor, % DT/% Yeast by weight ratio (or “food” to yeast ratio), is used (e.g., % DT=glucose), which offers information on the health status of the yeast. The controlling factor is used to control the status of the yeast throughout the entire process.

Methods of and system for growing and maintaining an optimized/ideal active yeast solution in the yeast tank and fermenter tank during the fermentation filling cycle are provided. A new yeast stage tank is used between the yeast tank and the fermenter tank allowing yeast to rapidly produce a huge amount of active young yeast cells for a fermenter during the filling period. A measurable and useful controlling factor, % DT/% Yeast by weight ratio (or “food” to yeast ratio), is used (e.g., % DT=glucose), which offers information on the health status of the yeast. The controlling factor is used to control the status of the yeast throughout the entire process.

The present invention relates to variants of a parent alpha-amylase. The present invention also relates to polynucleotides encoding the variants and to nucleic acid constructs, vectors, and host cells comprising the polynucleotides, and methods of using the variant enzymes.

The present invention relates to variants of a parent alpha-amylase. The present invention also relates to polynucleotides encoding the variants and to nucleic acid constructs, vectors, and host cells comprising the polynucleotides, and methods of using the variant enzymes.