Agricultural biomasses have significant potential to be widely used in cellulosic biofuel production. Lowering the cost of cellulases may speed up the commercialization process of biofuels. Both well pre-treated biomasses and enzymes with increased activity may decrease the dosage of cellulase.  We investigated the effects of pre-treatments on cellulases activity and also worked on improvement of cellulases expression and efficiency. The enzymes we are working on include the mesophilic Trichoderma reesei endocellulase Cel5A (EGII) and the hyperthermophilic endoglucanase from Pyrococcus horikoshii (EGph) and β-glucosidase from Pyrococcus furiosus (BGpf). These enzymes have been expressed in both Escherichia coli and Streptomyces lividans and their activities were tested using both Avicel and biomasses. Construction and characterization of EG-BG bifunctional molecules are in progress.  Future developments include the optimization of individual enzymes and bi-functional molecules by protein engineering.