An economic model was developed to help define how enzyme costs affect the choice of enzyme loadings and resulting sugar yields to maximize profitability for making jet and other fuels based on the combined operations of hot water pretreatment (Stage 1) and enzymatic hydrolysis (Stage 2).  First, the maximum sugar release was experimentally determined to occur at 180^oC following pretreatment of a 7.1 wt% solids slurry in a one-liter Parr reactor for 30 minutes.  At these conditions, the total monomeric plus oligomeric xylose concentration and yield were 11 g/l and 76 wt%, respectively, and the total monomeric plus oligomeric glucose concentration and yield were 1.8 g/l and 1.7 wt%, respectively.  Hydrolysis of the resulting solids with Spezyme CP cellulase at pH 4.8, 50^oC, and an enzyme loading of 44.7 FPU/g glucan in the raw corn stover resulted in yields of 68% and 20% of the potential glucose and xylose, respectively, in the raw feed.  The glucose and xylose yields for Stages 1 and 2 combined were 69.7% and 94%, respectively, at the highest enzyme loading 44.7 FPU/g glucan, with about 14% and 1.2% of the xylose and glucose, respectively, not accounted for in an overall mass balance.  Data was also developed for lower enzyme loadings of 5.6, 11.2, and 22.4 FPU/g, with longer times required to achieve lower yields than at the high loading.  A three-parameter enzymatic kinetic model developed by Shen and Agblevor was applied to simulate this experimental data at the four enzyme loadings applied, with model parameters determined by nonlinear regression.  The result was then incorporated into a profit model developed by Shen and Agblevor to define the optimal enzyme loading and hydrolysis time to maximize profit for producing fuels from sugars based on projected costs for enzymes and enzymatic hydrolysis and the value of the sugars released.  Through this approach, tradeoffs were identified between enzyme costs and optimal loadings and their effects on sugar yields that help define enzyme cost targets and pretreatment conditions.