• • Strain S3, identified as Bacillus cereus, exhibited a filter paper enzyme activity of 42.09 U·mL−1 and a corn stover degradation rate of 19.29% after 10 days, indicating robust cellulolytic potential for agricultural waste valorization.
• • Optimization via single-factor experiments and response surface methodology yielded a 1.43-fold increase in filter paper enzyme activity to 60.13 U·mL−1 under conditions of 76 h fermentation, 36°C, pH 6, and 4% inoculum, demonstrating significant process improvement.
• • The optimal carbon source was a mixture of microcrystalline cellulose and wheat bran at 4% total addition, while the optimal nitrogen source was soybean powder at 2%, providing a cost-effective and industrially scalable medium formulation.
• • The transparent circle-to-colony diameter ratio of 4.01±0.17 confirms high cellulase secretion, serving as a rapid screening metric for high-yield strains in industrial strain development.