Protein engineering has become the most important tool for enabling industrial application of biocatalysts. Advances in structure-guided methods and novel techniques for directed evolution and high-throughput screening have facilitated the design of enzymes with improved properties such as functional expression, stability, and catalytic activity. The utilization of lignocellulosic biomass for biofuels production is attractive because it is environmentally sustainable. However, commercialization of biomass biofuels requires efficient bioconversion of cellulosic material to sugar, which is largely hampered by biomass recalcitrance. In this chapter, we present the recent application of protein engineering techniques for maximizing the efficiencies of biocatalysts for biofuel production.