Submerged Agitated Cultures of Edible Ascomycetes and Basidiomycetes Grown on Carbon-Rich Waste Streams: Mycelial Mass Production and Volatile Compound Analysis

The present study explores the treatment and valorization of carbon-rich, low-cost waste streams—sugar beet molasses, expired rice, and wheat cereal hydrolysates—as substrates for submerged shake-flask cultures of edible ascomycetes (Morchella elata AMRL 63, Tuber aestivum AMRL 364) and basidiomycetes (Lentinula edodes AMRL 126, Agaricus bisporus AMRL 209) within a circular bioeconomy framework. Cultures were conducted under different C/N ratios (20 and 50) with or without the addition of olive oil or its emulsion. Among the tested species, the ascomycetes M. elata AMRL 63 and T. aestivum AMRL 364 outperformed the basidiomycetes in biomass production and substrate utilization. Supplementation with olive oil or its emulsion enhanced mycelial growth and lipid accumulation, while a higher C/N ratio (50) favored exopolysaccharide (EPS) synthesis. Lipid profiles were dominated by oleic (Δ9C18:1) and linoleic (Δ9,12C18:2) acids, with greater unsaturation observed in C/N = 20 cultures. Volatile analysis revealed species-specific aroma signatures, including characteristic truffle and morel compounds. The results underscore the feasibility of using waste streams for sustainable mushroom cultivation.