Extraction of nanochitin–glucan composite from Aspergillus niger with enhanced antibacterial activity

The conversion of fungal biomass into functional biopolymer materials offers a promising route for renewable material fabrication and sustainable waste valorization. Aspergillus niger (A. niger) mycelium is rich in chitin and glucan, yet its conversion into fibrous chitin-based nanomaterials remains insufficiently connected to biomass processing, nanofiber structure, and final material performance. Here, a scalable strategy is proposed for preparing partially deacetylated chitin–glucan complex nanofibers (CGCNFs) from A. niger . Specifically, A. niger was cultured in PD medium containing 12 g/L potato extract and 60 g/L glucose for 96 h. Subsequent treatments, including alkaline processing, deacetylation, and high-pressure homogenization, yielded CGCNFs with an average diameter of 9.86 ± 1.86 nm and an aspect ratio of 25. Compared with traditional methods, the proposed process achieved approximately 15–48% increase in CGCNFs yield and a 75–81% reduction in raw material costs, demonstrating markedly higher efficiency and economic feasibility. Characterization by FTIR, XRD and solid-state 13 C NMR confirmed enhanced surface functionalization of the CGCNFs. Moreover, the CGCNFs exhibited strong antibacterial activity, inhibiting more than 99% of Escherichia coli and Staphylococcus aureus . Notably, CGCNFs/PVA films displayed a tensile modulus of 4.2 GPa, representing a 162.5% increase relative to neat PVA films. This work provides a sustainable strategy for biomass conversion, renewable polysaccharide material fabrication, and the development of functional biopolymer films for food related applications.