Preparation and application of holocellulose, cellulose nanofibers, and silver-loaded cellulose nanofibers from passion fruit peel

In this study, we extracted holocellulose from passion fruit peel (PFP) and used it to prepare cellulose nanofibers (CNFs). Subsequently, we reduced silver nanoparticles (AgNPs) on the CNFs in situ. Using univariate and orthogonal tests, the best holocellulose yield was 56.95% under the following conditions: PFP (3 g) combined with pectinase (0.2 g), with reaction time (50 min), reaction temperature (40 °C), and fixed pH of 4.8. CNFs were obtained by adding 15 U/mL cellulase to the holocellulose material and maintaining at 50 °C for 15 h. The CNFs and silver nitrate were used as the substrate with glucose as the reducing agent to synthesize AgNPs. The obtained AgNP–CNFs complex exhibited excellent antibacterial properties, i.e., the diameter of the bacteriostatic zone reached 1.95 ± 0.08 cm in Escherichia coli. The AgNP–CNFs can be used in the food, medical, and chemical industries.