Antibacterial Komagataeibacter hansenii nanocellulose membranes with avocado seed bioactive compounds

Abstract

Biocompatible, mechanically stable, highly hydrophilic/swellable and safe antibacterial biomaterials are crucial for wound dressing and other applications in the health sector. Therefore, this study was conducted for the development of bacterial nanocellulose membranes, which were, for the first time, enriched with bacteriostatic and bactericidal effective avocado seed extracts prepared by different extraction techniques (ultrasonic, Soxhlet, high pressure with supercritical carbon dioxide). First, the production process of bacterial nanocellulose membranes from Komagataeibacter hansenii bacteria was optimized related to the fermentation media composition and culture conditions, resulting in bacterial nanocellulose membranes with up to 83% crystallinity and 54.5 g/L yield. The morphological structure of the membranes was varied further by using air- and freeze-drying processes. The Soxhlet and high pressure with supercritical carbon dioxide avocado seed extracts with the most charge negative surface (-33 mV) and smallest hydrodynamic size (0.1 µm) thus resulted in 100% reduction of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus with up to log reduction of 2.56 and up to 100% bactericidal efficacy after 24 h of exposure, and at 14 mg/g of avocado seed extracts integrated in the bacterial nanocellulose membranes homogeneously. The high swelling (up to 600%) and water retention ability of avocado seed extracts enriched bacterial nanocellulose membranes, with a biocidal release up to 2.71 mg/mL, shows potential for antibacterial applications in the biomedicine, cosmetics, and pharmaceutical industries.