TECHNOLOGY FOCUS - BIOLOGY - Preferred Method: The degradation takes place at a temperature below 100 degrees C. The aqueous solution exhibits a pH of greater than 10 and less than 12, preferably less than 11, before the treatment of the lignocellulosic material. The base is not added during the treatment. The lignocellulosic material is straw, bagasse, energy grass and/or glumes. The lignocellulosic material is present in the aqueous solution in a material density of 5-40 wt.%. The material enriched with cellulose and hemicellulose is treated with xylanase and/or a cellulase to obtain the sugar. The obtained sugars are fermented into alcohol, which is separated and recovered. The solid material after the treatment is reacted with xylanase after the treatment. The resulting fluid phase is converted to xylitol using a xylose dehydrogenase. The remaining solid material is further reacted with cellulase to obtain different fermentation products, or subjected to a thermal and thermo chemical conversion of the material, or undergoes a microbial transformation of the material by bacteria, yeasts and fungi, or subjected to delignification step to obtain a cellulose fiber material. After the separation of the (fermentation) products, the remaining solid material is fermented in a biogas plant and further processed into biogas. EXAMPLE - Wheat straw was crushed to a particle size of about 2 cm and was suspended in a reaction vessel (500 ml) with a solution (200 ml) consisting of water (49.5%), ethanol (50%) and hydrogen peroxide (0.5%). The suspension obtained was heated to 50 degrees C in a water bath, thermostated and the pH of the suspension was adjusted with aqueous sodium hydroxide solution to a initial pH of 12. The mixture was magnetically stirred at 200 revolutions per minute at 60 degrees C continuously for 24 hours. The solid material content was filtered and washed with distilled water (1 l). The substrate (100 mg) was pretreated for the enzymatic hydrolysis during each parallel attempt with 50 mM sodium acetate buffer (9.8 ml) of pH 4.8 and was mixed with Accellerase 1000 (RTM: Cellulase enzyme complex for lignocellulosic biomass hydrolysis) (200 mu l). The enzymatic hydrolysis was performed at 50 degrees C in a water bath shaker. The soluble monomers released from hexoses and pentoses were determined in the form of reducing sugars by dinitrosalicylic acid method in supernatant liquid (1 ml).