2C2T-Centre for Textile Science and Technology, Textile Engineering Department, University of Minho, Campus Azurem, 4800-058 Guimarães, Portugal.
Centre for Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal.
Carbohydr Polym. 2016 Jul 10;145:1-12. doi: 10.1016/j.carbpol.2016.03.009. Epub 2016 Mar 8.
This work studied the physical immobilization of a commercial laccase on bacterial nanocellulose (BNC) aiming to identify the laccase antibacterial properties suitable for wound dressings. Physico-chemical analysis demonstrates that the BNC structure is manly formed by pure crystalline Iα cellulose. The pH optimum and activation energy of free laccase depends on the substrate employed corresponding to pH 6, 7, 3 and 57, 22, 48kJmol(-1) for 2,6-dimethylphenol (DMP), catechol and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively. The Michaelis-Menten constant (Km) value for the immobilized laccase (0.77mM) was found to be almost double of that of the free enzyme (0.42mM). However, the specific activities of immobilized and free laccase are similar suggesting that the cage-like structure of BNC allows entrapped laccase to maintain some flexibility and favour substrate accessibility. The results clearly show the antimicrobial effect of laccase in Gram-positive (92%) and Gram-negative (26%) bacteria and cytotoxicity acceptable for wound dressing applications.
本工作研究了商业漆酶在细菌纳米纤维素（BNC）上的物理固定化，旨在确定适用于伤口敷料的漆酶抗菌性能。物理化学分析表明，BNC 结构主要由纯结晶 Iα 纤维素组成。游离漆酶的最适 pH 值和活化能取决于所使用的底物，分别为 2,6-二甲基苯酚（DMP）、儿茶酚和 2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）的 pH6、7、3 和 57、22、48kJmol(-1)。固定化漆酶的米氏常数（Km）值（0.77mM）几乎是游离酶（0.42mM）的两倍。然而，固定化和游离漆酶的比活性相似，表明 BNC 的笼状结构允许固定化漆酶保持一定的灵活性并有利于底物的可及性。结果清楚地表明，漆酶对革兰氏阳性（92%）和革兰氏阴性（26%）细菌具有抗菌作用，且细胞毒性可接受用于伤口敷料应用。
