Carbon-nitrogen metabolic coupling for optimized protein production of corn stover polysaccharides: From molecular...

The efficient bioconversion of polysaccharide-rich lignocellulosic agricultural residues into high-value products remains a significant challenge in sustainable agriculture. We investigated the molecular mechanisms of carbon‑nitrogen metabolic coupling during corn stover bioconversion through solid-state fermentation with Trichoderma longibrachiatum. Statistical optimization of fermentation conditions enhanced substrate nutritional value, achieving 17.57 % true protein content (53.45 % increase) and substantial lignocellulose degradation (cellulose 24.89 %, hemicellulose 23.54 %, lignin 22.28 %). Transcriptomic analysis revealed key metabolic coupling mechanisms, with cysteine supplementation significantly enhancing cellulolytic enzyme activities and protein accumulation. The optimized fermented corn stover increased dry matter intake and nutrient digestibility in buffalo feeding trials, while rumen microbiome analysis demonstrated shifts towards beneficial taxa and metabolic pathways. This study reveals the molecular interplay between polysaccharide metabolism and protein synthesis, providing a comprehensive strategy with dual benefits: environmental sustainability through efficient agricultural waste valorization and enhanced animal production through improved feed digestibility and nutrient utilization. This approach simultaneously addresses global food security concerns and environmental challenges associated with agricultural waste management.