Evaluation of nanocellulose carriers produced by four different bacterial strains for laccase immobilization.

Properties of bacterial nanocellulose (BNC) produced by four different strains were studied and compared for laccase immobilization. Scanning electron microscope inspection indicated the four types of BNC had obvious differences in fiber density, diameter and distribution. BNC hydrogel demonstrated the highest fracture stress of 2.44 Mpa and the highest Young's modulus of 12.76 Mpa. Brunauer-Emmett-Teller analysis suggested the four BNC had significant difference in specific surface area, total pore volume and average pore size. Laccase was immobilized on BNC carriers via adsorption. Kinetic studies showed that the four types of BNC-immobilized laccase had different affinity with substrate, and all types of immobilized laccase showed high operational stability after ten consecutive biocatalytic cycles of reaction. The results suggest that the structure diversity of BNC from various strains may directly result in different efficiency in laccase immobilization, and a looser fiber network in BNC with larger porosity is helpful for enzyme immobilization.