Plant biomass represents the major source for renewable bio-fuels. Cell walls constitute the major portion of plant biomass. The main challenge in sustainable production of ligno-cellulosic biofuel is overcoming the cell wall recalcitrance barrier. A number of cell wall components including lignin and hemicelluloses have been shown to contribute to this cell wall recalcitrance. Thus, removing or reducing the proportion of wall components that contribute to cell wall recalcitrance of ligno-cellulosic biomass is a key step in sustainable ligno-cellulosic biofuel production.