TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The ethanologen comprises Saccharomyces cerevisiae.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method further comprises: treating the first component to remove inhibitors; and treating the first component to increase the concentration of xylose. The step of maintaining the first component and ethanologen in the fermentation system is for a time of no less than 24 hours. The organism is capable fermenting xylose into a fermentation product. Preferred Components: The first component comprises a liquid component of the lignocellulosic material. The second component comprises a solid component of the lignocellulosic material. The lignocellulosic material comprises corn cobs, corn plant husks, corn plant leaves and corn stalks. The first component comprises sugar, where the ethanologen is supplied to the fermentation system at a concentration of 0.01-1 g per gram of sugar in the first component. The first component comprises xylose (2-5 wt.%). The ethanologen is an organism or yeast. The biomass comprises hemi-cellulose and the fermentation product has been produced by fermentation of xylose. The biomass comprises cellulose and the fermentation product has been produced by fermentation of glucose. The liquid component comprises xylose and glucose and the ethanologen comprises an organism capable of fermenting xylose into ethanol and glucose into ethanol. The first component comprises xylose, where the fermentation product comprises ethanol, and at least 75% of the xylose has been converted into ethanol by fermentation. The biomass is lignocellulosic biomass, the first component comprises pentose and the second component comprises cellulose and lignin. The pentose comprises xylose and the first fermentation product comprises a fermentation product produced by fermentation of xylose. The biorefinery further comprises a second treatment system to treat the second component into a treated second component from which hexose can be accessed for fermentation, a second fermentation system to produce a second fermentation product from the hexose by supplying an ethanologen to ferment the hexose, a distillation system to recover ethanol from the second fermentation product. The hexose comprises glucose. The fermentation product comprises at least 1.5% or at least 2% ethanol by volume. EXAMPLE - A sample was prepared having an initial xylose concentration of 4.7 wt.%. The sample was divided into subsamples, which were supplied with a yeast loading of 0.05-30 grams per liter (of sample) in a fermentation system to produce a fermentation product. The fermentation was conducted at approximately 32 degrees C and at a pH of 5.5 for 48 hours. The subsamples were analyzed for xylose concentration and ethanol concentration.