Extraction of a novel fungal chitin from Hericium erinaceus residue using multistep mild procedures

In this study, a novel fungal chitin was extracted from Hericium erinaceus residue using moderate chemical sequential extraction procedures. The effects of deproteinization conditions, including NaOH concentration, reaction temperature, and reaction time, on the chitin yield, purity, molecular weight (M_w), and degree of acetylation (DA) were investigated. Additionally, SEM, FTIR, XRD, NMR and TGA were applied to indicate the removal of non-chitin components from HER. Results suggested that the deproteinization processes meaningfully influence the chitin yield, purity, M_w, and DA. The chitin with most desirable parameters (yield of 16.30%, purity of 97.88%, M_w of 2.01 × 10⁵ g/mol, and DA of 77.67%) was obtained at low NaOH concentration of 2%, reaction temperature of 85 °C, and reaction time of 3 h. In addition, non-chitin components such as minerals, proteins, and pigments were mostly removed after the extraction. The results demonstrated that the Hericium erinaceus residue can lead to a high-quality chitin, which is useful for a broad range of applications.