NOVELTY - Fermenting sugars derived from plant material into a fermentation product in a fermentation medium using a fermenting organism, comprises adding one or more constituents comprising transketolase enzyme, thiaminepyrophosphate, or combinations to the fermentation medium.    USE - The method, processes, transgenic plant material, and modified fermenting organism fermenting sugars derived from plant material into a fermentation product in a fermentation medium using a fermenting organism; for producing the fermentation product from starch-containing material; and for producing the fermentation product from lignocellulose-containing material (all claimed).    ADVANTAGE - The method constituents increase ethanol yield and/or promote yeast quality or yeast proliferation. Also, the method is environment friendly cost effective, maximizes ethanol yield, effective, and can increase fermenting organism quality/quantity.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are:    (1) a process of producing the fermentation product from starch-containing material, comprising: (a) liquefying starch-containing material; (b) saccharifying the liquefied material; and (c) fermenting with one or more fermenting organisms, where one or more constituents comprising transketolase enzyme, thiaminepyrophosphate, or combinations are added to the fermentation medium;    (2) a process of producing the fermentation product from lignocellulose-containing material, comprising: (a) pre-treating lignocellulose-containing material; (b) hydrolyzing the material; and (c) fermenting with a fermenting organism, where one or more constituents comprising transketolase enzyme, thiaminepyrophosphate, or combinations are added to the fermentation medium;    (3) transgenic plant material transformed with a polynucleotide sequence encoding transketolase or progeny of such transgenic plant material capable of expressing transketolase; and    (4) a modified fermenting organism transformed with a polynucleotide encoding a transketolase, where the fermenting organism is capable of expressing transketolase at fermentation conditions.