Characterization of mycelia from wood-decay species by TGA and IR spectroscopy

Abstract: Wood-decay fungi have been mainly studied for their medicinal or nutraceutical properties, lignocellulolytic enzymes as well as their pathological role in plants. Recently they have also been recognized as a potential source of biocomposite materials due to the features of mycelial mats in several species. Chemical, physical-morphological and biological properties are affected by interspecific and intraspecific differences in composition of the cell wall regarding both major and minor constituents; thus, a preliminary characterization can optimize the strain selection for applied and research purposes. In the present study, 52 strains from 18 wood-decay fungal species were considered to build a general descriptive model based on the cell wall in the light of interspecific variability. Pure-cultured mycelia were dried and examined by thermogravimetric analysis (TGA) and Fourier transformed infrared spectroscopy (FTIR) to highlight the main different characteristics of each species. TGA profiles resulted more functional for a qualitative-quantitative description of major constituents (above all, β-glucans and chitin), whereas FTIR spectra are only qualitative and more difficult to analyze. Principal component analysis and cluster analysis confirmed the general descriptive model and allow interspecific comparison beyond intraspecific variability. In conclusion, TGA provides a simpler tool for screening of wood decay fungal strains and selection based on major cell wall constituents, namely chitin and glucans. Graphic abstract: [Figure not available: see fulltext.]