Method for digesting a biomass comprising lignin together with cellulose and/or hemicellulose

A method for digesting a biomass comprising lignin together with at least one of cellulose and hemicellulose, comprising the steps of:

• (a) contacting the biomass with a first solvent for dissolving at least one of the cellulose and the hemicellulose,
• (b) contacting at least one of the dissolved cellulose and the dissolved hemicellulose with a precipitant for forming a precipitate comprising at least one of the cellulose and the hemicellulose and wherein the precipitate includes a residual lignin, wherein the precipitant is selected from ethers, and esters, the ethers having 8 C-atoms or less that are selected from the group consisting of CPM-ether, methyl-tert butylether (MtB ether), ethyl-tert butylether (EtB ether,) propyl-tert butyl ether, butyl-tert butyl ether, dimethyl ether, methyl ethyl ether, diethyl ether, methyl propyl ether, ethyl propyl ether, methyl butyl ether, methyl pentyl ether, ethyl butyl ether, dipropyl ether, diisopropylether, methyl hexyl ether, ethyl pentyl ether, propyl butyl ether, methyl heptyl ether, ethyl hexyl ether, propyl pentyl ether, dibutyl ether, and their isomers, either alone or in any mixture thereof, the esters having 8 C-atoms or less that are selected from the group consisting of methyl acetate, ethyl acetate, ethyl acetoacetate, propyl acetate, isopropyl acetate, butyl acetate, t-butyl acetate, pentyl acetate, hexyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate, pentyl formate, hexyl formate, heptyl formate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, pentyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, methyl pentanoate, ethyl pentanoate, propyl pentanoate, methyl hexanoate, ethyl hexanoate, and their isomers, either alone or in any mixture thereof, and methyl pentanoate/ethyl acetate 1:3, methylpentanoate/ethyl acetate 2:3, anisole/ethyl acetate 1:3, xylol/MTB-ether 1:3, hexane/MTB-ether 1:3, isooctan/ethyl acetate 1:3, isoamylformate/ethyl acetate 1:1, and mixtures thereof;
• and
• (c) contacting the precipitate with a second solvent for removing the residual lignin from the precipitate.