METHOD FOR PRODUCING SUGAR SOLUTION

摘要

A method for producing a sugar solution by treating a cellulose-containing biomass with dilute sulfuric acid, said method comprising the below-mentioned steps (1) to (4). In the method, a higher treatment effect can be achieved compared with those achieved in the conventional treatment methods with dilute sulfuric acid. Step (1): a step of treating the cellulose-containing biomass with dilute sulfuric acid and then separating the resultant solution into a dilute sulfuric acid-treated solution and a cellulose-containing solid material. Step (2): a step of adding a cellulase to the cellulose-containing solid material to hydrolyze the cellulose-containing solid material, thereby producing a sugar solution. Step (3): a step of filtrating the dilute sulfuric acid-treated solution through a nano-filtration membrane at a pH of 2.5 or lower to separate out a sugar-rich solution as a non-filtrate and collect an aqueous sulfuric acid solution as a filtrate. Step (4): a step of reusing the whole or a portion of the aqueous sulfuric acid solution obtained in step (3) in the treatment with dilute sulfuric acid in step (1).