Turning food waste to antibacterial and biocompatible fungal chitin/chitosan monofilaments

Here, cell wall of a zygomycete fungus, Rhizopus delemar, grown on bread waste was wet spun into monofilaments. Using the whole cell wall material omits the common chitosan isolation and purification steps and leads to higher material utilization. The fungal cell wall contained 36.9% and 19.7% chitosan and chitin, respectively. Solid state NMR of the fungal cell wall material confirmed the presence of chitosan, chitin, and other carbohydrates. Hydrogels were prepared by ultrafine grinding of the cell wall, followed by addition of lactic acid to protonate the amino groups of chitosan, and subsequently wet spun into monofilaments. The monofilament inhibited the growth of Bacillus megaterium (Gram+ bacterium) and Escherichia coli (Gram- bacterium) significantly (92.2% and 99.7% respectively). Cytotoxicity was evaluated using an in vitro assay with human dermal fibroblasts, indicating no toxic inducement from exposure of the monofilaments. The antimicrobial and biocompatible fungal monofilaments, open new avenues for sustainable biomedical textiles from abundant food waste.

Automated summary

In this study, monofilaments were produced from the cell wall of Rhizopus delemar, a zygomycete fungus grown on bread waste. The monofilaments contained chitosan, chitin, and other carbohydrates, and showed significant antimicrobial activity against both Gram+ and Gram- bacteria. Furthermore, the monofilaments exhibited no cytotoxicity. These findings suggest that the fungal monofilaments could be utilized as sustainable biomedical textiles using abundant food waste.