Process for the production of carbohydrate cleavage products from a lignocellulosic material

Abstract

A process for the production of carbohydrate cleavage products, characterized by a combination of the measures that a lignocellulosic material is treated with an aqueous solution containing an alcohol, in particular a C 1-4 -alcohol or a phenol, and having a pH-value of between 11.0 and 14.0 in order to cleave lignocellulose and separate cleavage products from the material, whereby a material enriched with cellulose and hemicellulose is obtained, and the obtained material enriched with cellulose and hemicellulose is treated with at least one carbohydrate-cleaving enzyme in order to obtain the carbohydrate cleavage products.

1 . A process for the production of carbohydrate cleavage products, the process comprising:
 treating a lignocellulosic material with an aqueous solution containing an alcohol and having a pH-value of between 11.0 and 14.0 in order to cleave lignocellulose and separate cleavage products from the material, whereby a material enriched with cellulose and hemicellulose is obtained, and   treating the obtained material enriched with cellulose and hemicellulose with at least one carbohydrate-cleaving enzyme in order to obtain the carbohydrate cleavage products.   
     
     
         2 . A process according to  claim 1 , wherein the aqueous solution has a pH-value of between 11.0 and 13.0. 
     
     
         3 . A process according to  claim 1 , wherein the cleavage occurs at a temperature of below 100° C. 
     
     
         4 . A process according to  claim 3 , wherein the cleavage occurs at a temperature of below 40° C. 
     
     
         5 . A process according to  claim 1 , wherein straw, bagasse, energy grasses and/or spelts are used as a lignocellulosic material. 
     
     
         6 . A process according to  claim 1 , wherein the lignocellulosic material is present in the aqueous solution in a stock density of 5-40% by weight. 
     
     
         7 . A process according to  claim 1 , wherein the material enriched with cellulose and hemicellulose is treated with a xylanase and/or a cellulase in order to extract the sugars. 
     
     
         8 . A process according to  claim 1 , wherein the sugars obtained are fermented into alcohol which is separated and recovered. 
     
     
         9 . A process according to  claim 1 , wherein the decomposed solid is converted with a xylanase and the liquid phase obtained is converted into xylitol, and the remaining solid:
 is reacted further with cellulase in order to obtain different fermentation products;   or   is subjected to a thermal or thermochemical conversion;   or   is subjected to a microbial conversion by bacteria, yeasts or fungi;   or   is subjected to a further delignification step for the purpose of obtaining a cellulose fibre material.   
     
     
         10 . A process according to  claim 9 , wherein the decomposed solid is converted with a xylanase and the liquid phase obtained is converted into xylitol using a xylose dehydrogenase, and the remaining solid:
 is reacted further with cellulase in order to obtain different fermentation products;   or   is subjected to a thermal or thermochemical conversion;   or   is subjected to a microbial conversion by bacteria, yeasts or fungi;   or   is subjected to a further delignification step for the purpose of obtaining a cellulose fibre material.   
     
     
         11 . A process according to  claim 9 , wherein the solid remaining after the separation of the products is fermented in a biogas plant and is processed further into biogas. 
     
     
         12 . A process according to  claim 2 , wherein the cleavage occurs at a temperature of below 100° C. 
     
     
         13 . A process according to  claim 12 , wherein the carbohydrate cleavage products include a sugar. 
     
     
         14 . A process according to  claim 1 , wherein the alcohol includes a C 1-4 -alcohol or a phenol. 
     
     
         15 . A process according to  claim 14 , wherein straw, bagasse, energy grasses and/or spelts are used as a lignocellulosic material. 
     
     
         16 . A process according to  claim 15 , wherein the lignocellulosic material is present in the aqueous solution in a stock density of 5-40% by weight. 
     
     
         17 . A process according to  claim 16 , wherein material enriched with cellulose and hemicellulose is treated with a xylanase and/or a cellulase in order to extract the sugars. 
     
     
         18 . A process according to  claim 17 , wherein the sugars obtained are fermented into alcohol which is separated and recovered. 
     
     
         19 . A process according to  claim 18 , wherein the solid remaining after the separation of the fermentation products is fermented in a biogas plant and is processed further into biogas.