Effect of acid modification of Biochar derived from spent mushroom substrate on the production of oyster mushroom (Pleurotus ostreatus)

Spent mushroom substrate (SMS) disposal presents significant environmental challenges in the edible fungi industry. Converting SMS into biochar offers a promising resource utilization approach; however, the original biochar properties limit its effectiveness in mushroom cultivation applications. In this study, SMS biochar was modified by phosphoric acid treatment to form acid-modified mushroom substrates (AMMS), and the influence of acid-modified mushroom substrates on the production of oyster mushroom was evaluated. According to the obtained data, Acid modification significantly increased the surface area and micropore volumes of biochar. Fourier transform infrared spectroscopy (FTIR) analysis revealed the hydrophilicity and adsorption capacity of acid-modified biochar have been enhanced. The highest-performing treatments in AMMS showed 13-16% yield increases compared to unmodified biochar treatments, with harvest time advanced by 2.5 days. The safety assessment confirmed that all treatments with biochar added had no video security risks. In conclusion, phosphoric acid modification of SMS biochar significantly improves its performance as a mushroom cultivation substrate additive. This approach provides an effective strategy for SMS resource utilization and offers technical support for optimizing oyster mushroom cultivation practices.