Tiered valorization of corn straw-deer manure waste: Enhanced button mushroom quality coupled with functional characterization of stage-specific substrate for targeted industrial use

With escalating challenges in agricultural waste disposal, efficient waste utilization technologies are crucial for sustainable development. By innovatively employing deer manure and corn straw, this study systematically elucidated the dynamic substrate transformation patterns during mushroom cultivation, converting waste into edible products. Comparing corn straw-deer manure versus corn straw-chicken manure substrates for Agaricus bisporus cultivation showed similar yields (21.82 vs. 23.18 kg/m 2 ), but deer manure substrate produced mushrooms with superior agronomic traits, including higher individual mushroom weight, cap weight, and ratio of cap diameter to stipe length. Deer manure substrate significantly enhanced methionine content 3-fold (0.06 vs. 0.02 g/100 g) and improved cysteine levels. During cultivation, carbon content decreased from 45.60 % to 26.49 %, and nitrogen content increased from 1.49 % to 2.52 %. Cellulase (2.05 U/g) and laccase (8.96 U/g) reached their peak activities during the primordia formation stage, while xylanase exhibited its highest activity (16.38 U/g) during the mycelium growth stage. Microbial community analysis revealed distinct succession patterns, with deer manure substrate demonstrating superior Actinomycetota enrichment (79.33 % vs. 47.19 %) and enhanced cellulolytic bacterial abundance. A graded value-added strategy was established by analyzing the lignocellulosic composition and morphological changes in corn straw during A. bisporus cultivation using scanning electron microscopy, Fourier transform infrared spectroscopy, and quantitative biochemical analysis. Optimal applications were determined: products from the first and second turning stages (cellulose>30 %, hemicellulose>20 %, lignin≤16 %) for bioethanol production, products from the end of composting phases I and II (cellulose>18 %) for mushroom cultivation substrates, and products from the end of the first, second, and third flushes (cellulose<30 %, hemicellulose<11 %, lignin<16 %) for organic fertilizer production, maximizing resource potential of the corn straw-deer manure composite system.