Abstract: The invention relates to methods for identifying a hybrid organism, based on staining of parent cells with a dye, preferably a fluorescent dye. A preferred dye is a succinimidyl ester-coupled dye. The invention further relates to the resulting hybrid organism, preferably an interspecies hybrid organism, that is labelled with a dye.

Abstract: Novel genome alteration system for microorganisms The invention relates to a set of targeting constructs, comprising a first construct comprising a recognition site for an endonuclease, a first region of homology with a target gene of a microorganism, and a first part of a selection marker, and a second construct comprising a second part of the selection marker, a second region of homology with the target gene of the microorganism, and a copy of the endonuclease recognition site. The invention further relates to methods for altering a target gene in a microorganism, to methods for producing a microorganism, and to microorganisms that are produced by the methods of the invention.

Abstract: The present invention relates to novel xylose-fermenting yeast strains (for example, yeast of the genus Saccharomyces, e.g., S. cerevisiae) with an enhanced ability to ferment the xylose (and/or another pentose sugar) present in a lignocellulosic hydrolysate to a fermentation product(s) (for example, an alcohol (e.g., ethanol) or a sugar alcohol (e.g., xylitol)).

Abstract: The present invention relates to a method for producing a fermentation product from a sugar hydrolysate. The method comprises fermenting the sugar hydrolysate in a fermentation system with yeast to produce a fermentation broth comprising a fermentation product; introducing acid and an oxidant, such as chlorine dioxide, to the fermentation system so as to expose microbial contaminants in the fermentation system at one or more stages to chlorine dioxide and a pH of less than 3.0; and recovering the fermentation product. In one example of the invention, a yeast slurry obtained from a yeast recycle step is treated with acid and the oxidant.

Abstract: The present invention relates to novel xylose-fermenting yeast strains (for example, yeast of the genus Saccharomyces, e.g., S. cerevisiae) with an enhanced ability to ferment the xylose (and/or another pentose sugar) present in a lignocellulosic hydrolysate to a fermentation product(s) (for example, an alcohol (e.g., ethanol) or a sugar alcohol (e.g., xylitol)).

Abstract: The present invention relates to novel xylose-fermenting yeast strains (for example, yeast of the genus Saccharomyces, e.g., S. cerevisiae) with an enhanced ability to ferment the xylose (and/or another pentose sugar) present in a lignocellulosic hydrolysate to a fermentation product(s) (for example, an alcohol (e.g., ethanol) or a sugar alcohol (e.g., xylitol)).

Abstract: A method for obtaining a fermentation product from a sugar hydrolysate obtained from a feedstock containing hemicellulose, by (i) removing suspended fiber solids from said sugar hydrolysate to obtain a clarified sugar solution; (ii) fermenting xylose in the clarified sugar solution in a fermentation reaction with yeast to produce a fermentation broth comprising the fermentation product; (iii) separating the yeast from the fermentation broth to produce a yeast slurry; (vi) treating the yeast slurry thus obtained with an oxidant to kill microbial contaminants, thereby an oxidant-treated yeast slurry; (v) re-introducing at least a portion of the oxidant-treated yeast back to step (ii) to increase the concentration of yeast in said fermentation reaction; and (vi) recovering the fermentation product.

Abstract: A method for obtaining a fermentation product from a sugar hydrolysate obtained from a feedstock containing hemicellulose, by (i) removing suspended fiber solids from said sugar hydrolysate to obtain a clarified sugar solution; (ii) fermenting xylose in the clarified sugar solution in a fermentation reaction with yeast to produce a fermentation broth comprising the fermentation product; (iii) separating the yeast from the fermentation broth to produce a yeast slurry; (vi) treating the yeast slurry thus obtained with an oxidant to kill microbial contaminants, thereby an oxidant-treated yeast slurry; (v) re-introducing at least a portion of the oxidant-treated yeast back to step (ii) to increase the concentration of yeast in said fermentation reaction; and (vi) recovering the fermentation product.

Abstract: A method for producing a fermented solution enriched in xylose is provided. The sugar stream that is fermented results from the hydrolysis of a lignocellulosic feedstock and comprises at least a hexose and a pentose. The method comprises fermenting the sugar stream resulting from the hydrolysis of the lignocellulosic feedstock with a microorganism that preferentially ferments the hexose over the pentose. The fermenting is conducted under aerobic conditions and comprises continuously feeding the sugar stream to a fermentation reactor at a dilution rate that converts the hexose to cell mass preferentially over the pentose, thereby reducing the concentration of the glucose in the sugar stream so that the fermented solution thus produced is enriched in the pentose relative to said sugar stream.

Abstract: A method for obtaining a fermentation product from a sugar hydrolysate obtained from a feedstock containing hemicellulose, by (i) removing suspended fiber solids from said sugar hydrolysate to obtain a clarified sugar solution; (ii) fermenting xylose in the clarified sugar solution in a fermentation reaction with yeast to produce a fermentation broth comprising the fermentation product; (iii) separating the yeast from the fermentation broth to produce a yeast slurry; (vi) treating the yeast slurry thus obtained with an oxidant to kill microbial contaminants, thereby an oxidant-treated yeast slurry; (v) re-introducing at least a portion of the oxidant-treated yeast back to step (ii) to increase the concentration of yeast in said fermentation reaction; and (vi) recovering the fermentation product.

Abstract: The present invention relates to a method for producing a fermentation product from a sugar hydrolysate. The method comprises fermenting the sugar hydrolysate in a fermentation system with yeast to produce a fermentation broth comprising a fermentation product; introducing acid and an oxidant, such as chlorine dioxide, to the fermentation system so as to expose microbial contaminants in the fermentation system at one or more stages to chlorine dioxide and a pH of less than 3.0; and recovering the fermentation product. In one example of the invention, a yeast slurry obtained from a yeast recycle step is treated with acid and the oxidant.

Abstract: The present invention relates to novel xylose-fermenting yeast strains (for example, yeast of the genus Saccharomyces, e.g., S. cerevisiae) with an enhanced ability to ferment the xylose (and/or another pentose sugar) present in a lignocellulosic hydrolysate to a fermentation product(s) (for example, an alcohol (e.g., ethanol) or a sugar alcohol (e.g., xylitol)).

Abstract: A method for obtaining a fermentation product from a sugar hydrolysate obtained from a feedstock containing hemicellulose, by (i) removing suspended fiber solids from said sugar hydrolysate to obtain a clarified sugar solution; (ii) fermenting xylose in the clarified sugar solution in a fermentation reaction with yeast to produce a fermentation broth comprising the fermentation product; (iii) separating the yeast from the fermentation broth to produce a yeast slurry; (vi) treating the yeast slurry thus obtained with an oxidant to kill microbial contaminants, thereby an oxidant-treated yeast slurry; (v) re-introducing at least a portion of the oxidant-treated yeast back to step (ii) to increase the concentration of yeast in said fermentation reaction; and (vi) recovering the fermentation product.