PROCESS FOR PRETREATING LIGNOCELLULOSIC BIOMASS WITH HYDRATED INORGANIC SALT FOR OBTAINING CELLULOSIC AND HEMICELLULOSIC FRACTIONS

The present invention describes a process for the pretreatment of lignocellulosic biomass comprising: a) a step of acid hydrolysis of the biomass with an acid solution leading to a liquid fraction and to a solid fraction， b) a step of separation of the solid fraction and the liquid fraction， c) a step of drying the solid fraction， d) a step of cooking the dried solid fraction in a medium comprising at least one hydrated inorganic salt making it possible to obtain a solid fraction and a liquid fraction， e) a step of separation of the solid fraction and the liquid fraction obtained in step d) f) optionally a step of treatment of said solid fraction obtained in step e)， g) a step of enzymatic hydrolysis of said solid fraction obtained in step e) and / or f)， and in which at least part of the liquid fraction obtained in step b) is used for the growth of the microorganism producing the enzymes necessary for the enzymatic hydrolysis of step g).