Wood-derived lignin composition

A method for producing a hardwood-derived lignin composition, wherein the method comprises:

• i) providing a wood-based feedstock originating from wood-based raw material and comprising wood chips, wherein the wood-based raw material is hardwood, and subjecting the wood-based feedstock to pretreatment to form a fraction comprising solid cellulose particles, wherein pretreatment comprises subjecting the wood-based feedstock to at least one impregnation treatment to form an impregnated wood-based feedstock, subjecting the impregnated wood-based feedstock to steam explosion treatment to form a steam-treated wood-based feedstock, mixing the steam-treated wood-based feedstock with a liquid to form a slurry, and separating a liquid fraction and a fraction comprising solid cellulose particles from the slurry,
• wherein the total dry matter content of the fraction comprising solid cellulose particles is 8-20 weight-%, and wherein at most 3 weight-% of the wood shives in the fraction comprising solid cellulose particles are wider than 1 mm as determined by the Somerville method;
• ii) subjecting the fraction comprising solid cellulose particles from i) to an enzymatic hydrolysis process, wherein the amount of nitrogen that is entering with the enzymes into the enzymatic hydrolysis process is adjusted to 0.05-0.6 weight-%, based on the total dry matter content of the fraction comprising solid cellulose particles, and wherein the enzymatic hydrolysis process comprises:
• iia) subjecting the fraction comprising solid cellulose particles to a first enzymatic hydrolysis step for 8-72 hours to form a first hydrolysis product;
• iib) separating the first hydrolysis product into a solid fraction comprising lignin and a liquid carbohydrate fraction by a first solid-liquid separation process;
• iic) re-slurrying the separated solid fraction comprising lignin from iib) by mixing it with a liquid;
• iid) subjecting the re-slurried solid fraction comprising lignin to a second enzymatic hydrolysis step for 8-72 hours to form a second hydrolysis product;
• iie) separating the second hydrolysis product into a solid fraction comprising lignin and a liquid carbohydrate fraction by a second solid-liquid separation process;
• and
• iii) subjecting the solid fraction comprising lignin from the enzymatic hydrolysis process of ii) to at least one purification process to provide the lignin composition, wherein the at least one purification process in step iii) is continued until a lignin composition comprising 0.5-6 weight-% of soluble components is provided.