Patent ID: 8647850

Claim:
A method for the production of ethanol comprising: a) providing pretreated biomass comprising insoluble solids and polysaccharides; b) providing at least one saccharification enzyme for the conversion of polysaccharides to fermentable sugars; c) providing a prokaryotic ethanologen; d) preparing, in a bioreactor comprising agitation using an impeller, a saccharification-fermentation mixture comprising the pretreated biomass of a), the saccharification enzyme of b), and the prokaryotic ethanologen of c); and e) growing the prokaryotic ethanologen in the saccharification-fermentation mixture wherein, the concentration of total input insoluble solids in the saccharification-fermentation mixture is at least about 16% based on dry weight per liter, wherein the agitation provides an impeller power to mass radio of no more than about 0.2 watt/kg of total saccharification-fermentation mixture in the presence of biomass particles of size between 100 μm and 600 μm, and wherein the prokaryotic ethanologen produces ethanol.