Process for producing sugar solution

摘要

The present invention provides a process for producing a sugar solution having improved fermentability from cellulosic biomass as a raw material. This process for producing a sugar solution comprises: a step in which an alkali is added to a cellulosic-biomass-derived concentrated sugar solution to regulate the pH thereof to 7 or higher, thereby precipitating insoluble substances containing at least magnesium; and a step in which the resulting mixture is filtered with a microfiltration membrane to remove the insoluble substances and obtain a sugar solution as the penetrant.