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.

Textile fabric depilling is an important industrial application of cellulases. The depilling effect and achievement of desirable touch properties are among the applications sought by users. This process, although effective, is associated with significant tensile strength loss. The depilling mechanism is still a subject of controversy. In this work, we introduce a new perspective in understanding of the depilling mechanism, specifically we consider the contribution of interfacial properties. Cellulose Binding Domains (CBDs) obtained by ultrafiltration after digestion with a protease, were used in depilling experiments. Compared with cellulose, the performance of CBDs was very positive. In fact, when using CBD with residual hydrolytic activity, it was possible to achieve superior depilling treatments.