Characterization of two Tunisian strains of culinary oyster mushroom Pleurotus eryngii: Differences in the biopolymer composition

From the paper

Abstract

Two Tunissian strains of oyster mushrooms, identified as Pleurotus eryngii var. elaeoselini and var. ferulae, were investigated as promising for agricultural biodiversity based on the biopolymer composition of the mycelia, liquid cultural filtrate, and fruiting bodies. Results reveal the differences for these varieties in protein and d-glucan contents. The first strain exhibited high level of proteins in its fruiting bodies (17.7% w/w), while the second strain showed a high amount of fruiting body d-glucans (28.08% dry matter). Water-soluble polysaccharide fractions were isolated from the cultural filtrate of mycelia and fruiting bodies. Monosaccharide composition and linkages, FTIR, and NMR spectra of all these fractions confirmed the prevalence of α-d-mannan or mannogalactan over d-glucans. The cultural filtrate of Pleurotus eryngii var. elaeoselini was rich in α-d-mannan, while the mannogalactan was observed only in fruiting bodies of this strain. By contrast, Pleurotus eryngii var. ferulae provided a mixture of these two polysaccharides at different proportions both in cultural filtrate and fruiting bodies. The markedly diverse distribution of potential nutraceutical proteins and polysaccharides makes these two Pleurotus eryngii strains promising for increasing agricultural biodiversity in Tunisia and, generally, the North African region.