US Patent 7867400 Production of a fermentation product

A process of separating suspended solids from a fermentation liquor by subjecting the liquor to a solids-liquid separation stage,wherein the fermentation liquor is produced in a fermentation process for the production of a fermentation product,and which liquor comprises lignin,wherein the solids-liquid separation stage is assisted by a treatment system,characterised in that the treatment system comprises an anionic polymer,with the proviso that the treatment system and does not include a cationic polymer having an intrinsic viscosity (IV) of at least 4 dl/g.