NOVELTY - Digesting a biomass comprising lignin together with cellulose and/or hemicellulose, comprises: (a) contacting the biomass with a first solvent for dissolving the cellulose and/or the hemicellulose; (b) contacting the dissolved cellulose and/or hemicellulose with a precipitant for forming a precipitate comprising cellulose and/or hemicellulose and residual lignin, where the precipitant comprises alkanes, ethers or esters; and (c) contacting the precipitate with a second solvent for removing residual lignin from the precipitate.    USE - The method is useful for digesting a biomass comprising lignin, cellulose and/or hemicellulose. The method is useful for preparing solvents, biogas, biofuels, and/or other chemicals.    ADVANTAGE - The method: can be performed without using expensive equipment and difficult separation or recovery steps of solvents; and avoids detoxification step, hence the method is cost-effective.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an apparatus for performing the method, comprising: a first container (101, 201) for digesting a biomass comprising lignin, together with cellulose and/or hemicellulose, preferably a screw conveyor or a reactor, with a first introduction means (104, 204) for introducing a first solvent for dissolving the cellulose and/or the hemicellulose into the first container for contacting the biomass with the first solvent; a second introduction means (107, 207) for introducing a precipitant for forming a precipitate comprising cellulose and/or hemicellulose and residual lignin into the first container for contacting the dissolved cellulose and/or hemicellulose with the precipitant; and a third introduction means (110, 210) for introducing a second solvent for removing residual lignin from the precipitate into the first container for contacting the precipitate with the second solvent, where the first, second, and the third introduction means are arranged such as to permit a timely coordinated introduction of the first solvent, the precipitant, and the second solvent into the first container, and a re-feeding means (225) for recycling the precipitant is oriented such at the first container that the precipitant can be re-fed into the first container.    DESCRIPTION OF DRAWING(S) - The figure shows an apparatus for digesting a biomass.    First container (101, 201)    First introduction means (104, 204)    Second introduction means (107, 207)    Re-feeding means (225)    Third introduction means. (110, 210)