Mushroom By-Products as a Source of Growth Stimulation and Biochemical Composition Added-Value of Pleurotus ostreatus, Cyclocybe cylindracea, and Lentinula edodes

Spent mushroom substrates (SMSs) and mushroom basal bodies (MBBs) are significant by-products because of their nutrient content even after harvesting. This study aimed to evaluate the effect of these two by-products, derived from Agaricus bisporus (Ab) and Cyclocybe cylindracea (Cc) cultivation, as potential growth and biochemical composition add-value enhancers of edible mushroom mycelia such as Pleurotus ostreatus, C. cylindracea, and Lentinula edodes. Fungal growth substrates enriched with SMS and MBB extracts significantly affected the growth of mushroom mycelia. In particular, on P. ostreatus, the MBBs Ab and Cc extracts determined an increase in mycelial weight by 89.5%. Also, by-products influenced mushrooms' mycelial texture, which appeared more floccose and abundant in growth. FT-IR analysis showed that L. edodes mycelium, grown on MBB substrates, showed the highest increase in bands associated with proteins and chitin. Results demonstrated that mushroom by-products enhance mycelial growth and confer an enrichment of compounds that could increase mycelial resistance to pathogens and make a nutraceutical improvement.