Enzyme productivities of factorial recycle experiment samples. Based on total glucose produced and the total mass of enzyme protein added over the course of the experiment. Averages of duplicate experiments and error bars represent ± one standard deviation of the center point. The red line represents the productivity for the 72 hour hydrolysis with a 51.4 mg EP/g cellulose loading. Roman letters a-f indicate significantly different values by ANOVA (95% confidence intervals, pooled standard deviation 0.0045 (N=22)).