Patterns of major metabolites biosynthesis by different mushroom fungi grown on glucose-based submerged cultures

The biosynthetic potential of four basidiomycetes (Agrocybe aegerita, Flammulina velutipes, Ganoderma applanatum and Pleurotus pulmonarius) and one ascomycete (Morchella esculenta) was examined in regard to biomass, intracellular (endopolysaccharides and lipids) and extracellular (exopolysaccharides) compounds' production in liquid media with glucose as substrate, in static and agitated cultures. Exopolysaccharides' production presented significant negative correlation with biomass, endopolysaccharides and lipids, while biomass was positively related to the production of endopolysaccharides and lipids. Maximum values of biomass, endo- and exo-polysaccharides obtained were quite impressive: P. pulmonarius produced 22.5 g/L of biomass, A. aegerita 60.4 % (w/w) of endopolysaccharides and F. velutipes 1.2 g/L of exopolysaccharides. Polysaccharides and lipids synthesized at the early growth stages were subjected to degradation as the fermentation proceeded. Mycelial lipids of all strains were highly unsaturated, dominated by linoleic acid, whereas glucose was the main building block of endopolysaccharides. The ability of the examined mushroom fungi to synthesize in high quantities biomass and polysaccharides, products with biotechnological and medicinal interest, renders these fungi as potential candidates in sugar-based bio-refineries.