Fig. 6

Percent of theoretical sugar yields (top) and concentration of sugars (bottom) as a function of attritor milling time for glucose (left) and xylose (right) monomers and oligomers. Knife-milled (1 mm) fall-harvested UT-4b switchgrass was treated with gaseous ammonia at 150–160 °C for 1 h and milled in an attritor mill for 5, 10, 15 and 60 min (1/4″ spherical stainless steel beads, 40 lbs./500 g biomass). The samples were then saccharified using an enzyme consortium, Accellerase^® DUET at 28 mg protein/g glucan + xylan for the indicated times. The unmilled sample was saccharified using an enzyme consortium with the same components as Accellerase^® DUET. This formulation gave the same saccharification yields for glucose and xylose in the milled samples, within 5 % absolute, as the actual Accellerase^® DUET All yields are monomeric except for the brown bar which is the total soluble sugar (monomer + oligomer) at 120 h of saccharification. The saccharification was performed at a solids loading of 25 %