Hydrothermal-mechanical treatment of lignocellulosic biomass for production of fermentation products

A process for producing a fermentation product from biomass, said process comprising:

• (a) providing a feedstock containing lignocellulosic biomass and monomeric sugar that is physically bound therein;
• (b) combining said feedstock with a sugar-fermenting microorganism and cellulase enzymes, to create an initial mixture;
• (c) refining said initial mixture to mechanically release said monomeric sugar and to intimately mix said sugar-fermenting microorganism and said cellulase enzymes, wherein refining employs a first refiner selected from the group consisting of a hot-blow refiner, a hot-stock refiner, a blow-line refiner, a disk refiner, a conical refiner, a cylindrical refiner, an in-line defibrator, a homogenizer, and combinations thereof;
• (d) fermenting said monomeric sugar with said sugar-fermenting microorganism to produce an initial quantity of a fermentation product contained within an intermediate mixture;
• (e) digesting said intermediate mixture with a reaction solution consisting of steam and/or hot water in a digestor under effective reaction conditions to produce a digested stream containing cellulose-rich solids, hemicellulose oligomers, and lignin;
• (f) conveying said digested stream through a second refiner to reduce average particle size of said cellulose-rich solids;
• (g) introducing said digested stream to an enzymatic hydrolysis unit under effective hydrolysis conditions to produce cellulosic sugars from said cellulose-rich solids and optionally from said hemicellulose oligomers;
• and
• (h) fermenting said cellulosic sugars to produce an additional quantity of said fermentation product;
• wherein steps (a)-(h) are conducted in order.

A process for producing a fermentation product from biomass, said process comprising:

• (a) providing a feedstock containing lignocellulosic biomass and monomeric sugar that is physically bound therein;
• (b) combining said feedstock with a sugar-fermenting microorganism, to create an initial mixture;
• (c) refining said initial mixture to mechanically release said monomeric sugar and to intimately mix said sugar-fermenting microorganism, wherein refining employs a refiner selected from the group consisting of a hot-blow refiner, a hot-stock refiner, a blow-line refiner, a disk refiner, a conical refiner, a cylindrical refiner, an in-line defibrator, a homogenizer, and combinations thereof;
• (d) fermenting said monomeric sugar with said sugar-fermenting microorganism to produce an initial quantity of a fermentation product contained within an intermediate mixture;
• (e) digesting said intermediate mixture with a reaction solution consisting of steam and/or hot water in a digestor under effective reaction conditions to produce a digested stream containing cellulose-rich solids, hemicellulose oligomers, and lignin;
• (f) introducing said digested stream to an enzymatic hydrolysis unit under effective hydrolysis conditions to produce cellulosic sugars from said cellulose-rich solids and optionally from said hemicellulose oligomers;
• and
• (g) fermenting said cellulosic sugars to produce an additional quantity of said fermentation product;
• wherein steps (a)-(g) are conducted in order.