NOVELTY - An isolated polypeptide having beta -xylosidase activity, is new. The polypeptide includes polypeptide exhibiting at least 60% identity to mature polypeptide of SEQ ID NO: 2 or 4, or at least 80% identity to mature polypeptide of SEQ ID NO: 6, or polypeptide encoded by a polynucleotide exhibiting at least 60% identity to the mature polypeptide of SEQ ID NO: 1 or 3, or its cDNA sequences, or at least 80% identity to the mature polypeptide of SEQ ID NO: 5.    USE - The isolated polypeptide having beta -xylosidase activity is useful in whole broth formulation or cell culture composition, and for producing fermentation product, fermenting cellulosic or xylan-containing material and degrading or converting cellulosic or xylan-containing material (all claimed) for producing fuel, potable ethanol, and/or platform chemicals (e.g. acids, alcohols, ketones and gases).    ADVANTAGE - The polypeptide enables conversion of lignocellulosic feedstocks that are readily available in large amounts and production of ethanol fuel that is environmentally-friendly, avoids burning or land filling the materials, and provides cost-effective enzyme solutions for degradation of lignocellulose.    DETAILED DESCRIPTION - An isolated polypeptide having beta -xylosidase activity, is new. The polypeptide is chosen from (a) polypeptide exhibiting at least 60% identity to mature polypeptide of SEQ ID NO: 2 or 4, or at least 80% identity to mature polypeptide of SEQ ID NO: 6, (b) polypeptide encoded by a polynucleotide that hybridizes under at least medium-high stringency conditions with (i) the mature polypeptide encoding sequence of SEQ ID NO: 1 or 3, (ii) cDNA sequence of SEQ ID NO: 1 or 3, or (iii) full-length complement of (i) or (ii), or under at least high stringency conditions with the mature polypeptide encoding sequence of SEQ ID NO: 5 or its full-length complement, (c) polypeptide encoded by a polynucleotide exhibiting at least 60% identity to the mature polypeptide of SEQ ID NO: 1 or 3, or its cDNA sequences, or at least 80% identity to the mature polypeptide of SEQ ID NO: 5, (d) a variant of the mature polypeptide of SEQ ID NO: 2, 4, or 6 comprising a substitution, deletion, and/or insertion at one or more positions, and (e) fragment of the polypeptide of (a), (b), (c), or (d) that has beta -xylosidase activity. INDEPENDENT CLAIMS are included for the following:    (1) isolated polynucleotide encoding (a) the above-mentioned polypeptide, or (b) a signal peptide comprising or consisting of amino acids 1-18 of SEQ ID NO: 2, amino acids 1-16 of SEQ ID NO: 4, or amino acids 1-16 of SEQ ID NO: 6;    (2) recombinant host cell comprising (a) the above-mentioned polynucleotide operably linked to one or more control sequences that direct the production of the polypeptide, or (b) a gene encoding a protein operably linked to the polynucleotide encoding the signal peptide, where the gene is foreign to the polynucleotide;    (3) method for producing the above-mentioned polypeptide;    (4) transgenic plant, plant part or plant cell transformed with the above-mentioned polynucleotide encoding the polypeptide;    (5) method for producing a mutant of a parent cell, involves inactivating the polynucleotide encoding the above-mentioned polypeptide, which results in the mutant producing less of the polypeptide than the parent cell;    (6) double-stranded inhibitory RNA (dsRNA) molecule comprising a subsequence of the above-mentioned polynucleotide, where optionally the dsRNA is small interfering RNA (siRNA) or microRNA (miRNA) molecule;    (7) method for inhibiting expression of the polypeptide having beta -xylosidase activity in a cell, involves administering to the cell or expressing in the cell the above-mentioned double-stranded inhibitory RNA molecule;    (8) method for producing a protein, involves (a) culturing a recombinant host cell comprising a gene encoding a protein operably linked to the polynucleotide encoding the signal peptide, where the gene is foreign to the polynucleotide, under conditions conducive for production of the protein, and optionally (b) recovering the protein;    (9) method for degrading or converting a cellulosic or xylan-containing material, involves treating the cellulosic or xylan-containing material with an enzyme composition in the presence of the polypeptide having beta -xylosidase activity;    (10) method for producing a fermentation product, involves (a) saccharifying a cellulosic or xylan-containing material with an enzyme composition in the presence of the polypeptide having beta -xylosidase activity, (b) fermenting the saccharified cellulosic or xylan-containing material with one or more fermenting microorganisms to produce the fermentation product, and (c) recovering the fermentation product from the fermentation;    (11) method for fermenting a cellulosic or xylan-containing material, involves fermenting the cellulosic or xylan-containing material with one or more fermenting microorganisms, where the cellulosic or xylan-containing material is saccharified with an enzyme composition in the presence of the polypeptide having beta -xylosidase activity; and    (12) whole broth formulation or cell culture composition comprising the above-mentioned polypeptide.