NOVELTY - An isolated thermal tolerant GuxA polypeptide (I) derived from Acidothermus cellulolyticus, having a sequence (S1) of 1228 amino acids (aa). Fragments of (I) e.g., first catalytic domain glycoside hydrolase (CD-GH) 6, second CD-GH 12, carbohydrate binding domain (CBD) type III, and CBD type II, having 423, 231, 150, and 101 aas, respectively, is new. All sequences are fully disclosed in the specification.    USE - The set of primers (V) are useful for the detection of a polynucleotide encoding GuxA, by amplifying a nucleic acid sequence with (V), and correlating the amplified nucleic acid sequence with detected polynucleotide encoding GuxA. (I) is useful for assessing the carbohydrate degradation activity of Gux A, by analyzing a carbohydrate degradation in the presence of GuxA and a carbohydrate degradation in the absence of GuxA on a substrate, and comparing the carbohydrate degradation in the presence of GuxA with the carbohydrate degradation in the absence of GuxA. The method is also carried out in the presence of desired agent. (I) is useful for reducing cellulose in a starting material such as agricultural biomass (all claimed), to sugars which is useful in biofuel production. (I) is useful in the conversion of biomass to biofuels and biofuel additives, in detergents pulp and paper processing, food and feed processing, and in textile process. Fragments of (I) are useful to generate specific anti-GuxA antibodies. (I) is also useful to raise polyclonal and monoclonal antibodies that are useful in purifying GuxA, or detecting GuxA polypeptide expression, and as well as reagent tool for characterizing the molecular actions of GuxA polypeptides.    DETAILED DESCRIPTION - An isolated thermal tolerant GuxA polypeptide (I) derived from Acidothermus cellulolyticus, having a sequence (S1) of 1228 amino acids (aa). Fragments of (I) e.g., first catalytic domain glycoside hydrolase (CD-GH) 6, second CD-GH 12, carbohydrate binding domain (CBD) type III, and CBD type II, having 423, 231, 150, and 101 aas, respectively. (I) has a sequence (S1) of 1228 aas. The fragments of (I) such as first catalytic domain glycoside hydrolase (CD-GH) 6, second CD-GH 12, carbohydrate binding domain (CBD) type III, and CBD type II, having 423, 231, 150, and 101 aas, respectively; or a sequence having at least 70% identity with the above sequences.    INDEPENDENT CLAIMS are also included for the following;    (1) composition (II) comprising (I);    (2) an industrial mixture suitable for degrading cellulose, comprising (I);    (3) fusion protein (III) comprising (I) and a heterologous peptide;    (4) cellulase-substrate complex comprising (I) bound to cellulose;    (5) vector comprising the polynucleotide that encodes (I);    (6) host cell genetically engineered to express (I);    (7) composition comprising (I) and a carrier;    (8) isolated antibody (IV) that specifically binds to (I);    (9) production of (I);    (10) set of amplification primers (V) for amplification of a polynucleotide molecule encoding GuxA, comprising two or more sequences having 9 or more contiguous nucleic acids derived from the polynucleotide molecule; and    (11) probe (VI) for hybridizing to a polynucleotide encoding GuxA comprising a sequence of 9 or more contiguous nucleic acid derived from the polynucleotide molecule.    DESCRIPTION OF DRAWING(S) - The figure shows the schematic representation of the gene sequence and aa segment organization.