NOVELTY - An isolated, synthetic or recombinant nucleic acid, is new. The nucleic acid contains (a) a nucleic acid sequence exhibiting at least 70%, preferably 100% sequence homology to a 2232 base pair sequence (SEQ ID NO: 519) fully defined in the specification, (b) a nucleic acid sequence capable of hybridizing under stringent conditions to a nucleic acid of SEQ ID NO: 519, and (c) a nucleic acid sequence encoding a polypeptide having at least 70% homology to a 743 amino acid sequence (SEQ ID NO: 520) fully defined in the specification.    USE - The isolated, synthetic or recombinant nucleic acid is used for producing a polypeptide, and in expression cassette, vector or cloning vehicle for producing transformed cell chosen from bacterial cell, mammalian cell, fungal cell, yeast cell, insect cell and plant cell, and transgenic non-human animal, plant, plant part or plant seed. The transgenic non-human animal is mouse or rat. The non-human animal, plant, plant part or plant seed transformed cell produces the polypeptide encoded by the nucleic acid and having beta -xylosidase activity. The polypeptide is used in enzyme ensemble, or cocktail for depolymerization of cellulosic and hemicellulosic polymers to metabolizeable carbon moieties, treating or modifying a composition, hydrolyzing, breaking up or disrupting an arabinoxylan oligomer and for producing fuel. The composition is pharmaceutical composition, detergent composition, contact lens solution, waste treatment composition, disinfectant, biodefense agent, bio-detoxifying agent, fuel, or alcohol, preferably ethanol. The composition is optionally biomass or biomass material, paper, paper waste, recycled paper product, paper pulp, paper product, wood, wood product, wood pulp, textile, fabric, yarn, or fiber. The composition is a cellulose- or a cellulose derivative- composition. The composition is optionally beverage, food, feed, dairy product or nutritional supplement, where the food is dough, bread or baked product. The beverage, food, feed, or nutritional supplement is used for an animal. The fuel comprises bioethanol or gasoline-ethanol mix (all claimed).    DETAILED DESCRIPTION - An isolated, synthetic or recombinant nucleic acid, is new. The nucleic acid comprises (a) a nucleic acid sequence exhibiting at least 70%, preferably 100% sequence homology to a 2232 base pair sequence (SEQ ID NO: 519) fully defined in the specification, where the nucleic acid encodes a polypeptide having an beta -xylosidase activity, and optionally the sequence identities are determined by analysis with a sequence comparison algorithm or by a visual inspection, (b) a nucleic acid sequence capable of hybridizing under stringent conditions to a nucleic acid of SEQ ID NO: 519, where the nucleic acid encodes a polypeptide having an beta -xylosidase activity, and has at least 70% homology to SEQ ID NO: 519, and the stringent conditions include a wash step comprising a wash in 0.2X saline-sodium citrate (SSC) at 65 degrees C for 15 minutes, (c) a nucleic acid sequence encoding a polypeptide having at least 70% homology to a 743 amino acid sequence (SEQ ID NO: 520) fully defined in the specification, where the polypeptide has beta -xylosidase activity, (d) nucleic acid of (a), (b) or (c) encoding a polypeptide having an beta -xylosidase activity and lacking a signal sequence or a carbohydrate binding module, (e) nucleic acid of (a), (b), (c) or (d) encoding a polypeptide having an beta -xylosidase activity comprising a heterologous sequence, where optionally the heterologous sequence comprises a heterologous signal sequence, carbohydrate binding module, catalytic domain (CD), or their combination, and optionally the heterologous signal sequence, carbohydrate binding module or catalytic domain (CD) is derived from another oligomerase, cellulase or cellulolytic enzyme, or a non-oligomerase, cellulase or cellulolytic enzyme, or (f) nucleic acid sequence fully complementary to (a), (b), (c), (d) or (e). INDEPENDENT CLAIMS are included for the following:    (1) expression cassette, vector or cloning vehicle comprising the nucleic acid;    (2) transformed cell comprising the nucleic acid, or a vector or cloning vehicle, where the transformed cell produces a polypeptide encoded by the nucleic acid and having beta -xylosidase activity, if the cell is a human cell it is located ex vivo;    (3) transgenic non-human animal, plant, plant part or plant seed comprising the nucleic acid sequence, or a vector or cloning vehicle;    (4) isolated, synthetic or recombinant polypeptide (P1);    (5) method of producing a recombinant polypeptide;    (6) method of generating a variant of a nucleic acid;    (7) method for modifying codons in a nucleic acid encoding an beta -xylosidase polypeptide, involves (a) providing a nucleic acid encoding a polypeptide, and (b) identifying a codon in the nucleic acid of step (a) and replacing it with a different codon encoding the same amino acid as the replaced codon, and modifying codons in a nucleic acid encoding a cellulase;    (8) chimeric polypeptide comprising a first domain and at least a second domain;    (9) enzyme ensemble, or cocktail for depolymerization of cellulosic and hemicellulosic polymers to metabolizeable carbon moieties comprising a polypeptide (P1), or a polypeptide encoded by the nucleic acid;    (10) method of treating or modifying a composition, involves contacting the composition with a polypeptide (P1), polypeptide encoded by nucleic acid, composition or product of manufacture, or enzyme ensemble;    (11) method for hydrolyzing, breaking up or disrupting an arabinoxylan oligomer comprising composition;    (12) method for producing fuel; and    (13) method for processing a biomass material, involves contacting the biomass material with a polypeptide (P1), polypeptide encoded by the nucleic acid, composition or product of manufacture, or enzyme ensemble.