title: Enzymatic preparation of chitooligosaccharides by commercial lipase.
abstract: The effect of a commercial lipase on chitosan degradation was investigated. When four chitosans with various degrees of deacetylation were used as substrates, the lipase showed higher optimal pH toward chitosan with higher DD (degree of deacetylation). The optimal temperature of the lipase was 55°C for all chitosans. The enzyme exhibited higher activity to chitosans which were 82.8% and 73.2% deacetylated. Kinetics experiments show that chitosans with DD of 82.8% and 73.2% which resulted in lower Km values had stronger affinity for the lipase. The chitosan hydrolysis carried out at 37°C produced larger quantity of COS (chitooligosaccharides) than that at 55°C when the reaction time was longer than 6h, and COS yield of 24h hydrolysis at 37°C was 93.8%. Products analysis results demonstrate that the enzyme produced glucosamine and chitooligosaccharides with DP (degree of polymerization) of 2-6 and above, and it acted on chitosan in both exo- and endo-hydrolytic manner.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jinagnan University, Wuxi 214122, Jiangsu, China.
authors.forename: Dong-Xia
authors.initials: DX
authors.lastname: Lee
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jinagnan University, Wuxi 214122, Jiangsu, China; College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, Hubei, China. Electronic address: xiaws@jiangnan.edu.cn.
authors.forename: Wen-Shui
authors.initials: WS
authors.lastname: Xia
authors.affiliation: School of Medicine and Pharmaceutics, Jiangnan University, Wuxi 214122, Jiangsu, China.
authors.forename: Jia-Li
authors.initials: JL
authors.lastname: Zhang
keywords: Chitooligosaccharides; Chitosan; Chitosan degradation; Lipase