title: Identification of cellulase gene from the metagenome of Equus burchelli fecal samples and functional characterization of a novel bifunctional cellulolytic enzyme.
abstract: The metagenomic approach has been used successfully to isolate novel biocatalyst gene from uncultured microorganisms. The gene encoding exo-1,4-β-glucanase avicelase was amplified from the metagenome of the Equus burchelli fecal sample and cloned. The gene was found to be of 1,007 bp of nucleotide which encodes a protein of 318 amino acids with a calculated MW of 36 kDa. The deduced amino acid sequence was homologous with cellulases belonging to the glycosyl hydrolases 6 superfamily. The expressed protein was active towards the substrates avicel and carboxymethyl cellulose, indicating that it has bifunctional cellulolytic enzyme activity. The recombinant protein showed an activity of 5.23 U with specific activity of 6.8 U mg(-1) protein with the substrate avicel, while when CMC was used, an activity of 3.0 U with a specific activity of 4.2 U mg(-1) protein was achieved. Its optimum pH was determined to be 7.0 and optimum temperature of 35°C.
authors.affiliation: Animal Nutrition Division, National Institute of Animal Nutrition and Physiology, Bangalore, Karnataka, India. chandrasekhariah.naip@gmail.com
authors.forename: Matam
authors.initials: M
authors.lastname: Chandrasekharaiah
authors.forename: Appoothy
authors.initials: A
authors.lastname: Thulasi
authors.forename: Madiajagan
authors.initials: M
authors.lastname: Bagath
authors.forename: Duvvuri Prasanna
authors.initials: DP
authors.lastname: Kumar
authors.forename: Sunil Singh
authors.initials: SS
authors.lastname: Santosh
authors.forename: Chenniappan
authors.initials: C
authors.lastname: Palanivel
authors.forename: Vazhakkala Lyju
authors.initials: VL
authors.lastname: Jose
authors.forename: Koratokare Thirumalachar
authors.initials: KT
authors.lastname: Sampath
mesh_terms: D000818:Animals; D001419:Bacteria / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002480:Cellulase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D003001:Cloning, Molecular; D004795:Enzyme Stability; D018397:Equidae; D005243:Feces / Q000382:microbiology*; D007700:Kinetics; D054892:Metagenome; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D002482:Cellulose; D002480:Cellulase