Alkaline reagents such as ammonium hydroxide, sodium hydroxide, calcium hydroxide have been used as pretreatment reagents for bioconversion of lignocellulosic biomass.  The major role of alkaline pretreatment is delignification of biomass, which leads to improvement of the enzymatic digestibility. Alkyl aryl linkages in lignin are readily cleaved under alkaline conditions, and the reaction is controlled primarily by the bond structure, not sensitive to [OH^-] as long as the pH is greater than 10.  This prompts us to explore novel and inexpensive reagents suitable for alkaline pretreatment. Sodium carbonate is one such reagent; it is 4-6 times cheaper than sodium hydroxide, and easier to recover than NaOH. In this study, Sodium carbonate was used for pretreatment of switchgrass and corn stover. Optimum process conditions were identified taking enzymatic digestion and retention of carbohydrates as the criteria. The treatment parameters investigated were temperature, time of treatment and solid: liquid ratios. Switchgrass requires more severe pretreatment conditions than corn stover. Supplementation of hydrogen peroxide significantly increases delignification and digestibility.  For optimally treated switchgrass, glucan digestibility was 70% with cellulase enzyme loading of 15 FPU/g glucan. The glucan digestibility for corn stover was substantially higher at 80% with the same enzyme loading. Use of mixture of various hydrolytic enzymes (enzyme cocktail theory) is known to improve the efficiency of enzymatic saccharification. To verify this concept, enzymatic hydrolysis was investigated varying the composition of enzyme mix; cellulase, beta-glucosidase and xylanase. The physical characteristics of the treated biomass were also investigated by way of crystallinity index by XRD, surface area, and SEM. Results of these observables were correlated with enzymatic digestibility.