Agro-industrial residues represent valuable resources that can meet microorganism's requirements for growth and metabolite production. The goal of the present study is to formulate an optimum submerged fermentation medium for a newly isolated strain of Streptomyces sp. PO3, utilizing wheat bran as the base medium. Initially, the optimal pH, temperature, and wheat bran concentration were determined using the "one variable at a time" method. Subsequently, to enhance production efficiency, additional components were tested using multifactorial statistical approaches. The optimal conditions affecting protease production were determined by a central composite design. Kinetic production was monitored on the optimized medium for 216 h. The highest protease production was achieved through submerged fermentation at pH 9.0, 40 °C, and 25% wheat bran. Three minerals were statistically significant to improve protease production at a p < 0.05, and the optimum levels were NaCl 0.4, ZnSO4.7H2O 0.007, and CaCl2 0.015 (% w/v). Under these optimal conditions, peak activity was obtained after 96 h of incubation, with 2.87-fold increase compared to the base medium. Wheat bran can be used as cost-effective alternative to synthetic media for producing protease. [ABSTRACT FROM AUTHOR]