NOVELTY - Enhanced fermentation (M1) (200) of a plant material through a genetic modification of non-respiring yeast, comprises: removing (202) a mitochondrial genome from a diploid yeast; converting (204) the diploid yeast to a spheroplast, and converting a karl-1 yeast strain bearing a mitochondrial genome lacking a mitochondrial gene to a spheroplast; fusing (206) the diploid yeast to the karl-1 yeast strain bearing the mitochondrial genome lacking a mitochondrial gene; and producing (208) a transgenic non-respiring yeast, where the non-respiring yeast is capable of fermenting plant material.    USE - The method is useful in enhanced fermentation of a plant material through a genetic modification of non-respiring yeast for producing ethanol (claimed) or biofuels.    ADVANTAGE - The method utilizes the transgenic non-respiring yeasts, which: provide an ethanol production rate of 5-25% greater than a yeast containing an intact mitochondrial genome, or a yeast not comprising the dominant mitochondrial ATP synthase gene mutation stably integrated into the yeast; and have a doubling time equal to a yeast containing an intact mitochondrial genome, or to a yeast not comprising the dominant mitochondrial ATP synthase gene mutation stably integrated into the yeast and comprising the CAT5 nuclear gene (all claimed); and exhibit improved growth.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a transgenic non-respiring yeast (Y1) having a mitochondrial gene removed from mitochondrial DNA of the non-respiring yeast while leaving the rest of the yeast mitochondrial genome intact, where the removed mitochondrial gene is cytochrome-c oxidase (COX)-1, COX2, COX3, or cytochrome-b (COB);    (2) enhanced fermentation (M2) of the plant material through the genetic modification of transgenic non-respiring yeast, comprising: introducing the dominant mitochondrial ATP synthase gene mutation into the yeast; removing the mitochondrial DNA from the yeast; and producing the transgenic non-respiring yeast comprising the dominant mitochondrial ATP synthase gene mutation and lacking mitochondrial DNA, where the transgenic non-respiring yeast is capable of fermenting the plant material;    (3) a DNA construct for enhanced yeast fermentation of plant material through the genetic modification of transgenic non-respiring yeast, comprising the dominant mitochondrial ATP synthase gene mutation, and a selectable marker, where the dominant mitochondrial ATP synthase gene mutation is operably linked to the selectable marker;    (4) a transgenic non-respiring yeast (Y2) having the DNA construct stably integrated into the transgenic non-respiring yeast under conditions suitable for expression of the DNA construct in a transgenic non-respiring yeast, where the transgenic non-respiring yeast lacks the mitochondrial DNA;    (5) enhanced fermentation (M3) of the plant material through the genetic modification of non-respiring yeast (Y2), comprising: conducting a first transformation to delete a first copy of a catalase (CAT)-5 gene; conducting a second transformation to delete a second copy of a CAT5 gene; and isolating the non-respiring yeast strain bearing the deletion of first copy of CAT5 gene and the deletion of second copy of CAT5 gene, where the non-respiring yeast is capable of fermenting the plant material; and    (6) a transgenic non-respiring yeast (Y3), comprising at least one CAT5 gene deletion.    DESCRIPTION OF DRAWING(S) - The figure shows a flow diagram of a method for creating a yeast capable of enhanced fermentation through introduction of a mitochondrial genome lacking the COX1, COX2, COX3 or COB gene.    Method of enhanced fermentation (200)    Step of removing mitochondrial genome from diploid yeast (202)    Converting step (204)    Fusing step (206)    Producing step (208)