Hydrothermal treatment followed by enzymatic hydrolysis and hydrothermal carbonization as means to valorise agro- and forest-based biomass residues.

•Biomass composition defines its feasibility for alternative process routes.•High carbohydrate content was favourable for the saccharification route.•Hydrothermal carbonisation yields were high for biomasses with high lignin contents.•Methodology developed for lignin quantitation in the presence of protein and ash.