Abstract: This invention describes a process for the production of alcohols and/or solvents from cellulosic or lignocellulosic biomass that comprises at least the following stages: a) Alkaline chemical pretreatment of a cellulosic or lignocellulosic substrate; b) Optionally washing of the pretreated substrate; c) Enzymatic hydrolysis of the substrate that is pretreated and optionally washed using cellulolytic and/or hemicellulolytic enzymes that produce a hydrolyzate and a water-insoluble residue; d) Microorganism fermentation of the hydrolyzate that is obtained from stage c) and production of a fermentation must that contains at least one alcohol and/or solvent; e) Separation/purification of alcohol and/or solvent, and f) Separation of a cake that contains the insoluble residue, in which at least a portion of the cake that is obtained in stage f) is sent into at least one reactor for regeneration of cellulose, before being recycled downstream from stage a) for alkaline chemical pretreatment.