Abstract

Cultivation of edible mushrooms on urban wastes represents one of the most economically and cost-effective organic recycling processes. An effective tool to identify necessary nutrients for the production of fruiting bodies on the specialty substrates is mycelium growth. Hence, mycelium of king oyster mushroom (Pleurotus eryngii) were experimentally evaluated on cardboard and spent coffee ground (SCG) substrates for the mycelial growth rate, density and primordial formation. Studies were carried out using five different substrate formulations viz., 100% cardboard (TS1), 100% SCG (TS2), 50% cardboard+50% SCG (TS3), 70% cardboard+30% SCG (TS4) and 30% cardboard+70% SCG (TS5). The efficiency of different yeast extract concentrations (i.e. 1, 5, 10, 20, 30 and 50 g/l) as a supplement in potato dextrose agar media (PDA) on P. eryngii growth was also determined. The concentration of 1 g/l of yeast extract showed the best effects on mycelial growth and primordia formation of P. eryngii, while high concentration of yeast extract (550 g/l) did not show any beneficial influence. Combination between cardboard and SCG, especially substrate formulations of 30% cardboard+70% SCG increased mycelial density and number of primordial formations of P. eryngii compared to the substrates of cardboard or SCG alone. The results revealed a potential opportunity for commercial cultivation of edible mushrooms, especially P. eryngii for utilization of different recyclable residues as well as urban generated wastes reduction.