Cultivation technology optimization and identification of secondary metabolites from elm oyster mushroom <i>Hypsizygus ulmarius</i> (Bull.) Redhead (Agaricomycetes) through GC-MS metabolomic profiling from India

<i>Hypsizygus ulmarius</i>, a novel oyster mushroom species, offers potential scope due to its low-cost production, high biological efficiency, and notable nutritional, medicinal, and therapeutic properties. The present study standardized commercial cultivation technology for <i>H. ulmarius</i> in the Trans-Gangetic Plains of India. The mycelium grew well on potato dextrose agar and carrot extract broth at pH 8.0 and temperature 25 C. Wheat straw supplemented with the cotton seed hull at the rate of 10.0% dose, spawned with pearl millet grain spawn at the rate of 5.0% spawn dose, gave the highest mushroom yield (953.66 g/0.4 kg dry substrate) with biological efficiency (238.41%). The first flush sporocarps were freeze-dried for physicochemical characterization, revealing 16 strong peaks and 8 functional groups via Fourier transform infrared (FTIR) analysis. Particle size averaged 45.97 µm of mushroom powder, and scanning electron microscopy (SEM) analysis showed diverse surface textures. Gas chromatography–mass spectrometry metabolic profiling identified 20 key secondary metabolites each from hexane and methanolic extracts, with therapeutic uses that are valuable for pharmaceutical, nutraceutical, and food industry applications.