TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Polypeptide: The new isolated polypeptide having beta-glucosidase activity comprises:(1) a sequence comprising 863-amino acid sequence (SEQ ID NO. 2), or its fragment comprising amino acids 20-863;(2) a sequence having at least 85, 90 or 95% identity with amino acids 20 to 863 of (1), or its variant comprising conservative substitution, deletion and/or insertion of its one or more amino acids; or(3) a sequence encoded by a polynucleotide contained in plasmid pEJG113, which is contained in Escherichia coli NRRL B-30695.Preferred Cell: The mutant cell further comprises a gene encoding a native or heterologous protein.Preferred Method: Degrading cellulose- and hemicellulose-containing biomass comprises treating the biomass with the polypeptide or host cell and recovering the degraded biomass. The method further comprises treating the biomass with endo-l,4-beta-glucanase and exo-l,4-beta-D-glucanase. Producing a mutant of a parent cell comprises disrupting or deleting a nucleotide sequence encoding the polypeptide, which results in the mutant producing less of the polypeptide than the parent cell. Producing a protein comprises cultivating the mutant cell under conditions conducive for production of the protein and recovering the protein. Producing a polynucleotide having a mutant nucleotide sequence comprises introducing at least one mutation into the mature polypeptide coding sequence comprising 3060 bp and recovering the polynucleotide comprising the mutant nucleotide sequence.Production (claimed): Producing the polypeptide comprises cultivating a cell, which in its wild-type form is capable of producing the polypeptide, under conditions conducive for production of the polypeptide and recovering the polypeptide. The method also comprises cultivating a host cell comprising a nucleic acid construct comprising a nucleotide sequence encoding the polypeptide under conditions conducive for production of the polypeptide and recovering the polypeptide. The method also comprises cultivating a host cell comprising the mutant polynucleotide