Bioconversion of Spent Mushroom Substrate (SMS) of Button Mushroom for Cultivation of Oyster Mushroom (Pleurotus florida)

Mushrooms offer a sustainable solution to global food security by converting agricultural waste into nutritious protein. Pleurotus species are particularly valuable, requiring simple cultivation methods thus optimizing substrate combinations of organic wastes can significantly enhance mushroom yields and production efficiency. The present study evaluated the bioconversion potential of spent mushroom substrate (SMS) from button mushroom cultivation for enhancing the growth, yield, and nutritional quality of oyster mushroom (Pleurotus florida). Different combinations of wheat straw and SMS were tested, with the 4:1 ratio (wheat straw + SMS) (T5) emerging as the most effective treatment. Results showed that T5 significantly reduced spawn running (16 days), pinhead initiation (20 days), and harvesting periods (26, 32, and 41 days for three flushes) compared to the SMS-alone control (22, 28, and 36–55 days). The highest yield (1316.99 g/bag) and biological efficiency (87.73%) were recorded in T5, along with superior morphological traits such as maximum fruiting bodies (87.25/bag), stalk length (6.78 cm), and cap diameter (3.54 cm). Moisture content was optimized (~90%), and dry weight peaked at 135.60 g in T5. The study demonstrates that supplementing SMS with wheat straw (4:1 ratio) enhances P. florida productivity and offers an efficient waste-to-food solution.