Lytic polysaccharide monooxygenases and cellulases on the production of bacterial cellulose nanocrystals

Cellulose nanocrystals are a renewable biomaterial with nanoscale properties which have useful applications. In this study, an enzymatic treatment, an approach much more environmentally friendly than the traditional harsh acid hydrolysis, was performed to obtain bacterial cellulose nanocrystals (BCNC). The combination of an oxidation by a lytic polysaccharide monooxygenase (LPMO) and a hydrolysis with a mixture of glycosyl hydrolases was effective to produce nanocrystals from bacterial cellulose. Morphology and size were confirmed by electron microscopy and laser diffraction, respectively. Thermal stability was also measured and determined to be higher relative to native bacterial cellulose. Additionally, it was found that the negative charges generated by the LPMO increased the dispersion of the nanocrystals in aqueous solution, measured by the zeta potential. The BCNC were used to coat pre-existing cellulosic materials. The obtained composites displayed improved mechanical properties, an elevated water retention capacity, and impermeability to oil. These attractive features could lead BCNC-containing polymer nanocomposites to make an impact in the field of biocompatible and biodegradable packaging materials.