TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Composition: In (C1), the thermostable AviIII peptide further comprises a linker and a signal sequence. The GH74 catalytic domain of the thermostable AviIII peptide further comprises a length of about 730-760 amino acids. The CBD III of the thermostable AviIII peptide further comprises a length of about 80-150 amino acids, preferably 90 amino acids. (C1) further comprises a nucleic acid sequence having about 70 % or 80 % sequence identity to a fully defined AviIII nucleotide sequence (S4) as stated in specification.Preferred Industrial Mixture: (II) further comprises a detergent.Preferred Polynucleotide: (III) comprises a nucleic acid sequence having about 90 % or 80 % sequence identity to (S4). (III) comprises a nucleic acid sequence having about 90 % sequence identity to the nucleic acid sequence encoding (S1), (S2) or (S3). (III) further comprising a nucleic acid sequence encoding a heterologous protein in frame with the polynucleotide molecule encoding AviIII peptide. The heterologous protein is a peptide tag. The peptide tag is 6-His, thioredoxin, hemagglutinin, GST, or OmpA signal sequence tag. The heterologous protein is a substrate targeting group. (III) is operably linked to a transcriptional or translational regulatory sequence. The transcriptional or translational regulatory sequence comprises a transcriptional promoter or enhancer. Preferred Polypeptide: (IV) has a sequence with 90 % identity with any one of the sequence from (S1)-(S3) or with a sequence having 70 % sequence identity with any one of the sequence from (S1)-(S3).Preferred Fusion Protein: In (V), the heterologous peptide is a substrate targeting group or a peptide tag. The heterologous peptide is an agent that promotes polypeptide oligomerization. The agent is a leucine zipper.Preferred Host Cell: (VI) is a plant cell, fungi, bacterial cell or yeast.Preferred Antibody: (VII) is a polyclonal or monoclonal antibody.Preferred Method: (M1) further involves isolating the AviIII polypeptide from the incubated host cells. The host cell is genetically engineered to express a selectable marker. The host cell further comprises a polynucleotide molecule encoding one or more polypeptide molecules chosen from glycoside hydrolase family of proteins. The glycoside hydrolase is a thermostable glycoside.In (M2), an increase in carbohydrate degradation activity in the presence of the agent of interest demonstrates stimulation of AviIII activity and where a decrease in carbohydrate degradation activity demonstrates inhibition of AviIII activity. The carbohydrate is cellulose. The agent of interest is an antibody. EXAMPLE - Genomic DNA was isolated from Acidothermus cellulolyticus and purified by banding on cesium chloride gradients. Genomic DNA was partially digested with Sau 3A and separated on agarose gels. DNA fragments in the range of 9-20 kilobase pairs were isolated from the gels. The purified Sau 3A digested genomic DNA was ligated into the Bam HI acceptor site of purified EMBL3 lambda phage arms. Phage DNA was plated with Escherichia coli LE392 in top agar which contained the soluble cellulose analog, carboxymethylcellulose (CMC). The plates were incubated overnight (12-24 hours) to allow transfection, bacterial growth and plaque formation. Plates were stained with Congo Red followed by destaining with 1 M NaCl. Lambda plaques harboring endoglucanase clones showed up as unstained plaques on a red background. Lambda clones which screened positive on CMC-Congo Red plates were purified by successive rounds of picking, plating and screening. Template DNA was constructed using a 9 kilobase Bam HI fragment obtained from the 14.2 kilobase lambda clone SL-3 prepared from A. cellulolyticus genomic DNA. Cycle sequencing was performed using the template and primers. The sequencing primers were 26-30 nucleotides in length. The open reading frame (ORF) was found in the 9 kilobase Bam HI fragment, and C-terminal of E1 was termed AviIII. An ORF of 336 base pairs and a corresponding amino acid sequence was deduced. The amino acid sequence deduced was determined to have significant homology to known cellulases. Sequence alignments and comparisons of the amino acid sequences of the A. cellulolyticus AviIII catalytic domain (amino acids 37-776) and Aspergillus aculeatus Avicelase III polypeptides were prepared, using the ClustalW program (Thompson J. D et al. (1994), Nucleic Acids Res. 22:4673-4680). The amino acid sequence alignment of the GH74 domain indicated that the amino acid sequence of AviIII catalytic domain was homologous to the amino acid sequence of a known GH74 family catalytic domains for A. aculeatus Avicelase III (endoglucanase).