NOVELTY - Producing monosaccharides, sugar based chemicals, biofuels or materials together with sulfonated lignin from lignocellulosic biomass, comprises: (a) pretreating a lignocellulosic biomass in a sulfite cooking step; (b) separating the pretreated lignocellulosic biomass from step (a) into a liquid spent sulfite liquor (SSL) phase, and into a pulp; (c) hydrolyzing the pulp from step (b) into a sugar chemistry platform; (d) optionally further processing the monosaccharides from step (c); and (e) direct conversion or further processing the sulfonated lignin of the liquid phase from step (b).    USE - The process is useful for producing monosaccharides, biofuels or materials together with sulfonated lignin from lignocellulosic biomass, sugar based chemicals (claimed), e.g. ethanol and butanol.    ADVANTAGE - The process is cost-effective and reduces enzyme consumption.    DETAILED DESCRIPTION - Producing monosaccharides, sugar based chemicals, biofuels or materials together with sulfonated lignin from lignocellulosic biomass, comprises: (a) pretreating a lignocellulosic biomass in a sulfite cooking step; (b) separating the pretreated lignocellulosic biomass from step (a) into a liquid spent sulfite liquor (SSL) phase comprising 50% or more of the lignin of the lignocellulosic biomass in the form of sulfonated lignin, and into a pulp comprising 70% or more of the cellulose of the lignocellulosic biomass; (c) hydrolyzing the pulp from step (b) into a sugar chemistry platform comprising monosaccharides; (d) optionally further processing the monosaccharides from step (c) resulting in useful chemicals, biofuels and/or proteins; and (e) direct conversion or further processing the sulfonated lignin of the liquid phase from step (b) into useful chemicals and/or materials.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of preparing monosaccharides, sugar based chemicals, biofuels or materials together with sulfonated lignin from lignocellulosic biomass.