Bacterial Cellulose from Tobacco Waste Extract and Its Silver Composite: A Potential Wound Dressing Material

The high cost of conventional carbon sources has limited the widespread application of bacterial cellulose (BC). In this study, tobacco stem waste extract (TWE) was evaluated as an alternative substrate for BC production via fermentation with Gluconacetobacter xylinus, and a silver-loaded composite (BC-Ag) was further developed for potential wound dressing applications. Medium optimization with the addition of citric acid and (NH₄)₂SO₄ effectively alleviated salt stress and acid inhibition inherent to TWE, achieving a BC yield of 2.40 ± 0.12 g/L while preserving a native cellulose I crystalline structure and three-dimensional nanofibrous network. The resulting TWE-BC exhibited enhanced mechanical properties (ultimate tensile strength: 0.67 MPa; Young's modulus: 1.56 MPa) and improved thermal stability (glass transition temperature: 58.5 °C). The BC-Ag composite, fabricated via in situ chemical reduction, contained 8.84 wt% silver and demonstrated potent antibacterial activity against Staphylococcus aureus and Escherichia coli, along with favorable sustained-release behavior. Cytotoxicity assays confirmed good biocompatibility, with cell viability exceeding 70% at extract concentrations of 12.5-50%. In a rat infected-wound model, the BC-Ag dressing effectively eradicated local infection and significantly accelerated wound healing compared to commercial medical gauze, pure BC, and silver-loaded gauze controls. Collectively, this work presents a sustainable and potentially cost-effective strategy for valorizing tobacco waste into a high-value BC-based wound dressing material.