isolated polypeptide, isolated polynucleotide, recombinant host cell, methods of producing the polypeptide, of producing a parent cell mutant, of inhibiting expression of a polypeptide, of producing a protein, for degrading or converting a cellulosic material, of producing a product fermentation, fermenting a cellulosic material, transgenic plant, part of the plant or plant cell transformed with a polynucleotide, double-stranded inhibitory RNA molecule (rnads), and complete broth formulation or cell culture composition.