Chitosan from Virgin and SFE-Spent Fungi as a Raw Material for Disinfecting Gels

The valorization of extraction residues from biomass waste through a cascade approach contributes significantly to promote circular economy practices and facilitates the transition toward more sustainable functional materials, like chitosan. Virgin and spent fungal biomass, previously subjected to supercritical fluid extraction (SFE) using CO2, was further processed through demineralization and deproteinization to isolate chitin. This chitin was then deacetylated to obtain chitosan, and the yield of each step was evaluated. Although the extraction process requires further optimization, all the samples were characterized using infrared spectroscopy to assess compositional changes resulting from the treatments and compared with commercial counterparts. Chitosan solutions in acidic water were used to formulate hydroalcoholic gels, with ethanol pretreatment enabling compatibility between chitosan and alcohol. This study highlights the potential of chitosan—sourced from shrimps or fungi—as a sustainable raw material for disinfecting-gel applications, offering promising insights into its role in polymer-based formulations.