Integrating coffee parchment into a circular bioeconomy model for sustainable Pleurotus mushroom cultivation

Aim: This study examined the influence of coffee parchment (CP) particle size on growth, yield, morphology, and color quality of Pleurotus ostreatus and Pleurotus citrinopileatus, aiming to optimize the valorization of agro-industrial coffee waste through mushroom cultivation. Methods: Three CP particle size classes, raw CP (RCP), medium CP (MCP), and fine CP (FCP), were prepared and tested as substrates under controlled conditions. Growth traits (spawn running, primordial initiation, fruiting time), morphological parameters (pileus number, diameter, stipe length), yield indices [total yield, biological efficiency (BE), and production rate (PR)], and cap color (L*, a*, b*) were assessed. Data were analyzed using ANOVA and Duncan’s test at p < 0.05. Results: Particle size significantly affected all parameters. MCP and FCP accelerated colonization and primordia initiation by up to 7–8 days compared with RCP. Mushrooms cultivated in the FCP achieved the highest yields (377.2 ± 18.5 g for P. ostreatus; 355.0 ± 17.0 g for P. citrinopileatus), BE (75.2% and 72.0%), and PR (156.7% and 150.5%). Morphological traits were also improved, with larger and more abundant fruiting bodies on MCP and FCP. Color analysis indicated darker caps and a higher red hue on MCP substrates, suggesting enhanced pigment biosynthesis. Overall, P. ostreatus outperformed P. citrinopileatus, though both species responded positively to substrate refinement. Conclusions: CP particle size is a critical determinant of Pleurotus cultivation performance. Finer substrates improved yield, efficiency, and crop earliness, while enhancing commercial quality. These findings demonstrate the potential of physical substrate engineering to promote circular bioeconomy strategies and valorize lignocellulosic residues in coffee-producing regions.