title: Characterization of an alkalophilic extracellular chitosanase from Bacillus cereus GU-02.
abstract: An alkalophilic extracellular chitosanase (ACTase) was characterized from the culture supernatant of Bacillus cereus GU-02. Kinetic properties of ACTase produced from B. cereus GU-02 after cultivation in anaerobic condition, alkaline medium (pH 10) at 37°C for 3 days were investigated. ACTase was found to be stable in alkaline pH range from 8 to 10. Interestingly, optimum pH and temperature were estimated to be 10 and 37°C, respectively, where ACTase showed chitosan degrading activity (87%), which was enhanced by 15% in the presence of calcium ions (8 mM). The ACTase produced from B. cereus GU-02 was partially purified from the culture supernatant, and its enzymatic activity was kinetically characterized. The Vmax and Km were estimated with a chitosan (degree of deacetylation, DD 92% as substrate) as 0.038 U/min/μg protein and 0.327 μM, respectively. A combination of the TLC and MALDI-TOF MS results showed that the chitosan oligosaccharides obtained from the hydrolysis of high molecular weight chitosan (HMWC) by ACTase of the B. cereus GU-2 comprise oligomers with degree of polymerization (DP) mainly from dimers to pentamers. High production of ACTase and chitooligosaccharides may be useful for various industrial and biological applications.
authors: Department of Pharmaceutical Science, Gachon University, 191 Hambakmoeiro, Yeonsu-dong, Yeonsu-gu, InCheon 406-799, Republic of Korea.
authors: Bon Geun
authors: BG
authors: Goo
authors: Department of Life Science, College of Bionano, Gachon University, 191 Hambakmoeiro, Yeonsu-dong, Yeonsu-gu, InCheon 406-799, Republic of Korea. Electronic address: jkpark@gachon.ac.kr.
authors: Jae Kweon
authors: JK
authors: Park
mesh_terms: D001409:Bacillus cereus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D002236:Carbohydrate Conformation; D048271:Chitosan / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics
chemical_list: D001426:Bacterial Proteins; D048271:Chitosan; D006026:Glycoside Hydrolases; C019868:chitosanase
keywords: Alkalophilic chitosanase; Bacillus cereus; Chitooligosaccharides; Chitosan; Kinetic properties