title: Oxidation of primary hydroxyl groups in chitooligomer by a laccase-TEMPO system and physico-chemical characterisation of oxidation products.
abstract: The aim of this study was to investigate the oxidation of chitooligomer by a laccase-TEMPO system which had not previously been examined. Chitooligomer was treated with laccase and TEMPO in order to evaluate the potential of a laccase-TEMPO system to improve the moisture absorption, moisture retention, and antioxidant abilities of chitooligomer. Chitooligomer was prepared by degradation of high molecular weight chitosan with hydrogen peroxide followed by oxidation using a laccase-TEMPO system. (13)C NMR and carboxylate ion content detection results indicated that the laccase-TEMPO system could selectively oxidise the C6 hydroxyl group of the chitooligomer into carboxyl group; molecular weight distribution changes suggest that the structure of the oxidised product had changed and the molecular size and molecular weight decreased with the molecules in aqueous solution having a compact structure. Oxidation of chitooligomer by a laccase-TEMPO system resulted in a significant improvement in the moisture absorption, moisture retention and antioxidant abilities. The oxidised product has potential application values in the pharmaceutical and cosmetics industries.
authors.affiliation: Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science & Technology, 13th Avenue, Tianjin Economic-Technological Development Area, Tianjin 300457, China. Electronic address: jcpei@tust.edu.cn.
authors.forename: Jicheng
authors.initials: J
authors.lastname: Pei
authors.affiliation: Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science & Technology, 13th Avenue, Tianjin Economic-Technological Development Area, Tianjin 300457, China.
authors.forename: Yunbei
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science & Technology, 13th Avenue, Tianjin Economic-Technological Development Area, Tianjin 300457, China.
authors.forename: Zhenghui
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science & Technology, 13th Avenue, Tianjin Economic-Technological Development Area, Tianjin 300457, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Bu
authors.affiliation: Tianjin Key Laboratory of Pulp & Paper, Tianjin University of Science & Technology, 13th Avenue, Tianjin Economic-Technological Development Area, Tianjin 300457, China.
authors.forename: Fangdong
authors.initials: F
authors.lastname: Zhang
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D052160:Benzothiazoles / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D042845:Laccase / Q000737:chemistry*; D010084:Oxidation-Reduction; D013451:Sulfonic Acids / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D003497:Cyclic N-Oxides; D013451:Sulfonic Acids; D014867:Water; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D017665:Hydroxyl Radical; D048271:Chitosan; D006861:Hydrogen Peroxide; D042845:Laccase; C003959:TEMPO
keywords: Chitooligomer; Laccase; Oxidation; TEMPO