Submerged cultivation of selected macro-fungi to produce mycelia rich in β-glucans and other bioactive compounds, valorizing side streams of the food industry

Abstract

This study reports the valorization of four side-streams derived from the food industry as fermentation media to cultivate edible and medicinal macrofungi of the genera Cyclocybe sp., Ganoderma sp., Grifola sp., Hericium sp., Morchella sp., Pleurotus sp., Schizophyllum sp. and Trametes sp.. Initial screening experiments revealed the suitability of brewer’s spent grain extract (BSGE) and diluted wine distillery effluent (WDE) as the sole carbon sources for significant mycelial mass production. Subsequent fermentations investigated the effect of static and agitated conditions on biomass production, protein content and glucan content of fungal biomass. Considerably higher biomass and concentrations of total glucans, α-glucans and β-glucans were determined in macrofungi cultivated in BSGE compared to WDE. Agitated BSGE-based cultures of Schizophyllum commune resulted in the maximum biomass synthesis (27.6 g/L), while the highest total glucans of 70.8 % w/w with a β-glucan content of 57.2 % w/w were determined for G. lingzhi, when the culture was also agitated. The protein content of mycelia ranged from 12.3 up to 26.5 % w/w in the strains that were examined. ATR-FTIR spectra of the mycelia demonstrated the characteristic bands associated with fungal polysaccharides.