Production of a fermentation product

Abstract

A process of producing fermentation product comprising, forming an acidified suspension of particulate plant derived material comprising a first polysaccharide which is more readily hydrolysable and a second polysaccharide which is more difficult to hydrolyse; allowing the first polysaccharide to undergo hydrolysis under conditions such that the first polysaccharide is hydrolysed, thereby forming a mixture of an aqueous liquor containing dissolved sugar and a solid residue containing the second polysaccharide; subjecting the acidic mixture to one or more separation stages in which the solid residue and aqueous sugar liquor are substantially separated from each other; passing the aqueous liquor to a fermentation stage where the dissolved sugars are acted upon by a microorganism in a broth to produce a fermentation product; and separating the fermentation product from the broth, characterised in that the separation stage uses one or more flocculating agent(s) to form a waste by-product.