title: Purification and characterization of an exochitinase from Bacillus thuringiensis subsp. aizawai and its action against phytopathogenic fungi.
abstract: A chitinolytic enzyme from Bacillus thuringiensis subsp. aizawai has been purified and its molecular mass was estimated ca. 66 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was able to hydrolyze chitin to chitobiosides but not carboxymethylcellulose, cellulose, pullulan, and laminarin. Optimal pH and temperature were detected at 6 and 50 degrees C, respectively. Stability, in the absence of substrate, was observed at temperatures less than 60 degrees C and pH between 5 and 8. Enzyme activity was significantly inhibited by K+ and EDTA and completely inhibited by Hg2+. Purified chitinase showed lytic activity against cell walls from six phytopathogenic fungi and inhibited the mycelial growth of both Fusarium sp. and Sclerotium rolfsii. The biocontrol efficacy of the enzyme was tested in the protection of bean seeds infested with six phytopathogenic fungi.
authors.affiliation: UNIDA-Instituto Tecnológico de Veracruz, Mexico.
authors.forename: Luis Morales
authors.initials: LM
authors.lastname: de la Vega
authors.forename: J Eleazar
authors.initials: JE
authors.lastname: Barboza-Corona
authors.forename: Maria G
authors.initials: MG
authors.lastname: Aguilar-Uscanga
authors.forename: Mario
authors.initials: M
authors.lastname: Ramírez-Lepe
mesh_terms: D000935:Antifungal Agents / Q000302:isolation & purification* / Q000378:metabolism; D001413:Bacillus thuringiensis / Q000201:enzymology*; D002688:Chitinases / Q000302:isolation & purification* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005658:Fungi / Q000187:drug effects / Q000472:pathogenicity; D013025:Glycine max / Q000382:microbiology
chemical_list: D000935:Antifungal Agents; D002688:Chitinases