title: Thermostable chitinase from Cohnella sp. A01: isolation and product optimization.
abstract: Twelve bacterial strains isolated from shrimp farming ponds were screened for their growth activity on chitin as the sole carbon source. The highly chitinolytic bacterial strain was detected by qualitative cup plate assay and tentatively identified to be Cohnella sp. A01 based on 16S rDNA sequencing and by matching the key morphological, physiological, and biochemical characteristics. The cultivation of Cohnella sp. A01 in the suitable liquid medium resulted in the production of high levels of enzyme. The colloidal chitin, peptone, and K2HPO4represented the best carbon, nitrogen, and phosphorus sources, respectively. Enzyme production by Cohnella sp. A01 was optimized by the Taguchi method. Our results demonstrated that inoculation amount and temperature of incubation were the most significant factors influencing chitinase production. From the tested values, the best pH/temperature was obtained at pH 5 and 70°C, with Kmand Vmaxvalues of chitinase to be 5.6mg/mL and 0.87μmol/min, respectively. Ag+, Co2+, iodoacetamide, and iodoacetic acid inhibited the enzyme activity, whereas Mn2+, Cu2+, Tweens (20 and 80), Triton X-100, and EDTA increased the same. In addition, the study of the morphological alteration of chitin treated by enzyme by SEM revealed cracks and pores on the chitin surface, indicating a potential application of this enzyme in several industries.
authors.affiliation: National Institute of Genetic Engineering and Biotechnology, Department of Industrial and Environmental Biotechnology, Bioprocess Engineering Group, Tehran, Iran.
authors.forename: Nasrin
authors.initials: N
authors.lastname: Aliabadi
authors.affiliation: National Institute of Genetic Engineering and Biotechnology, Department of Industrial and Environmental Biotechnology, Bioprocess Engineering Group, Tehran, Iran. Electronic address: aminzade@nigeb.ac.ir.
authors.forename: Saeed
authors.initials: S
authors.lastname: Aminzadeh
authors.affiliation: National Institute of Genetic Engineering and Biotechnology, Department of Industrial and Environmental Biotechnology, Bioprocess Engineering Group, Tehran, Iran.
authors.forename: Ali Asghar
authors.initials: AA
authors.lastname: Karkhane
authors.affiliation: National Institute of Genetic Engineering and Biotechnology, Department of Industrial and Environmental Biotechnology, Bioprocess Engineering Group, Tehran, Iran.
authors.forename: Kamahldin
authors.initials: K
authors.lastname: Haghbeen
mesh_terms: D001407:Bacillus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D002244:Carbon / Q000378:metabolism; D002688:Chitinases / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation; D004795:Enzyme Stability / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D008670:Metals; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D007477:Ions; D008670:Metals; D012336:RNA, Ribosomal, 16S; D010758:Phosphorus; D002244:Carbon; D002688:Chitinases; D009584:Nitrogen
keywords: Biochemical characterization; Chitinase; Cohnella sp. A01; Isolation; Thermostable