Sustainable Production of Macrocybe indica Mushrooms: Enhancing Cultivation Performance, and Nutritional and Bioactive Properties Through Substrate Evaluation

Mushroom cultivation offers a sustainable route to convert agro-industrial residues into nutritious food while reducing environmental waste. Macrocybe indica (basionym Calocybe indica) is a particularly attractive basidiomycete for mushroom production in warm climates. This study evaluated four substrates—wheat straw (WHS), beech sawdust (BSD), and their combinations with grape marc (GMW and GMB, respectively)—with and without a casing layer, by assessing M. indica cultivation performance and the bioactive compound content of the mushrooms produced. Wheat straw with casing exhibited the highest yield and biological efficiency (153%), indicating that straw-based substrates are preferable for commercial production. Grape marc incorporation reduced yield but significantly enhanced protein content, total phenolics, antioxidant activity, ergosterol, and several individual phenolic acids and triterpenic compounds, with strong substrate–mushroom correlations observed for protocatechuic acid, caffeic acid, and ursolic acid. Beech sawdust-based substrates favoured β-glucan and ergothioneine content. ATR-FTIR spectroscopy combined with Principal Component Analysis showed clear differentiation in the composition of mushrooms grown on substrates with or without grape marc. These findings reveal a functional trade-off between agronomic efficiency and nutraceutical enhancement, demonstrating that strategic substrate selection can direct M. indica cultivation toward either maximum yield and/or enhanced functional food value, supporting circular bioeconomy approaches to mushroom cultivation.