Compositions and methods for increasing the expression and/or accumulation of cellobiohydrolase enzyme in the vacuoles of plant cells are provided. The method involves targeting the enzyme to the vacuoles through the use of a barley polyamine oxidase (BPAO) vacuole sorting signal peptide. Plants transformed with an expression construct encoding the vacuole sorting signal peptide operably linked to the cellobiohydrolase enzyme direct expression of the polypeptide to the vacuoles of the plant cells. Transgenic plants, seeds, and plant tissues, and plant parts are provided. Downstream uses of transgenic plants or plant material expressing the constructs of the invention include agronomical and industrial uses, for example, human food, animal feed, biofuel, industrial alcohol, fermentation feedstocks, and the like.