NOVELTY - An isolated thermostable GuxA polypeptide (I) molecule comprising a fully defined sequence of 1228 (S1), 423 (S2), 150 (S3), 231 (S4) or 101 (S5) amino acids as given in the specification, or an amino acid sequence having at least 70% sequence identity with (S1) to (S5), is new.    USE - (I) is useful for detection of a polynucleotide encoding (I) which involves amplifying a nucleic acid sequence with a set of amplification primers comprising two or more sequences of 9 or more contiguous nucleic acids derived from the polynucleotide molecule of (I), and correlating the amplified nucleic acid sequence with detected polynucleotide encoding (I). (I) is useful for assessing the carbohydrate degradation activity of GuxA which involves analyzing a carbohydrate degradation in the presence or absence of (I) on a substrate, and comparing the carbohydrate degradation in the presence or absence of (I). (I) is useful for assessing the carbohydrate degradation activity of (I) in the presence of an agent of interest which involves analyzing a carbohydrate degradation in the presence (I) and a carbohydrate degradation in the presence of GuxA and the agent of interest on a substrate exposed, and comparing the carbohydrate degradation in the GuxA treated substrate with the carbohydrate degradation in the GuxA treated substrate in the presence of the agent of interest. An increase in carbohydrate degradation activity in the presence of the agent of interest demonstrates stimulation of GuxA activity and where a decrease in carbohydrate degradation activity demonstrates inhibition of GuxA activity. The carbohydrate is cellulose and the agent of interest is an antibody. (I) is useful for reducing cellulose in a starting material which involves administering (I) to the starting material. The method further comprises administering a second polypeptide molecule chosen from the glycoside hydrolase family of proteins. The polypeptide molecule of (I) is thermostable. The starting material is agricultural biomass or municipal solid waste (all claimed).    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a composition (II) comprising a substantially purified thermostable GuxA peptide having a first catalytic domain GH6, a second catalytic domain GH12, a carbohydrate binding domain (CBD) type 3, and CBD type 2;    (2) an industrial mixture (III) suitable for degrading cellulose, such mixture comprising (II);    (3) a fusion protein (IV) comprising (II);    (4) a cellulase-substrate complex comprising (I) bound to cellulose;    (5) a vector comprising the polynucleotide molecule that encodes (I);    (6) a host cell (V) genetically engineered to express (I);    (7) a composition comprising (I) and a carrier;    (8) an isolated antibody (VI) that specifically binds to (I);    (9) producing (I);    (10) a set of amplification primers for amplification of a polynucleotide molecule encoding GuxA, comprising two or more sequences comprising 9 or more contiguous nucleic acids derived from the polynucleotide molecule of (I); and    (11) a probe for hybridizing to a polynucleotide encoding GuxA, comprising a sequence of 9 or more contiguous nucleic acids derived from the polynucleotide molecule of (I).