Extraction of chitin from flammulina velutipes waste: A low-concentration acid pretreatment and aspergillus Niger fermentation approach

Int J Biol Macromol. 2024 Jul;273(Pt 2):133224. doi: 10.1016/j.ijbiomac.2024.133224. Epub 2024 Jun 17.


In recent years, with the booming of the edible mushroom industry, chitin production has become increasingly dependent on fungi and other non-traditional sources. Fungal chitin has advantages including superior performance, simpler separation processes, abundant raw materials, and the absence of shellfish allergens. As a kind of edible mushroom, flammulina velutipes (F. velutipes) also has the advantages of wide source and large annual yield. This provided the possibility for the extraction of chitin. Here, a procedure to extract chitin from F. velutipes waste be presented. This method comprises low-concentration acid pretreatment coupled with consolidated bioprocessing with Aspergillus niger. Characterization by SEM, FTIR, XRD, NMR, and TGA confirmed that the extracted chitin was β-chitin. To achieve optimal fermentation of F. velutipes waste (80 g/L), ammonium sulfate and glucose were selected as nitrogen and carbon sources (5 g/L), with a fermentation time of 5 days. The extracted chitin could be further deacetylated and purified to obtain high-purity chitosan (99.2 % ± 1.07 %). This chitosan exhibited a wide degree of deacetylation (50.0 % ± 1.33 % - 92.1 % ± 0.97 %) and a molecular weight distribution of 92-192 kDa. Notably, the yield of chitosan extracted in this study was increased by 56.3 % ± 0.47 % compared to the traditional chemical extraction method.

Keywords: Biological fermentation; Chitin; Edible mushroom waste; Extraction.

MeSH terms

  • Acids / chemistry
  • Aspergillus niger* / metabolism
  • Chitin* / chemistry
  • Chitin* / isolation & purification
  • Fermentation*
  • Flammulina* / chemistry
  • Molecular Weight
  • Waste Products


  • Chitin
  • Waste Products
  • Acids