SELECTION OF WOOD DECAY FUNGAL STRAINS WITH MEDICINAL PROPERTIES USEFUL FOR DEVELOPMENT OF MYCO-MATERIALS

Recently researchers are focusing their attention on the potential of wood decay fungi (WDF) as a source for biotechnological and industrial applications. Chemical composition, mycelial texture, ease of cultivation, and lack of sporification make these organisms particularly suitable for developing mycomaterials. In the Myco-Advanced leaTher matERials (MATER) project different strains of wood decay fungi (many of them considered medicinal mushrooms too) were isolated using 2% malt extract agar (MEA) medium enriched with hydrogen peroxide and maintained at 4 °C and -80 °C. The identification of the strains was confirmed by molecular analysis of the ITS region. Based on growth rate, colour, homogeneity, consistency of the mycelium, at first 21 strains were chosen to be chemically characterised through scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Three strains were selected in consideration of their different cell wall chemical composition (high content of α-glucans, β-glucans or chitin) to evaluate how these differences could influence the mechanical and chemical characteristics of myco-materials.The fungal strains were cultivated in liquid submerged dynamic fermentation (both flasks and bioreactor). Later on, chitin and glucans were crosslinked with acetic acid and plasticized with glycerol in order to obtain flexible sheets. Abortiporus biennis, Fomitopsis iberica and Stereum hirsutum strains resulted to be adapted to produce material with adequate flexibility. Thermogravimetric analysis (TGA) allowed us to evaluate the principal chemical components, providing a semi-quantitative indication on mat composition. The material obtained from each species was mechanically tested in terms of tear strength, elongation at break, and Young’s modulus. Taking all the results into account, there was evidence of a correlation between chitin content and material mechanical response.