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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]

Screening of new producing strains is required to meet the constant industrial demand for useful enzymes. In this context, an actinobacteria was isolated from the olive pomace, tested for extracellular lipase production, and identified by partial 16S rDNA sequencing. Then, the physicochemical characteristics of the enzyme are determined. Strain is a member of Streptomyces genus. Lipase was partially purified at 62.5 times, with a yield of 14.83% and a specific activity of 337.5 U/mg. Optimum activity was achieved at pH 7.0 and 60°C; it was completely preserved at pH 6.0 to 9.0, and more than 70% at 40 to 70°C, after 1 hour. The metal ions: K+, Na+, Ca2+, Co2+, Cu2+, Fe2+, Mg2+, Mn2+, and Zn2+ had no significant impact. Lipase activity was stable with ethylene diamine tetra acetic acid (EDTA), sodium dodecyl sulfate (SDS), H2O2, Triton x100, and Tween 80. Moreover, it was enhanced in butanol, chloroform, ethyl acetate, isopropanol, isobutyl acetate, hexane, petrol ether, and toluene. This enzyme can be suitable for various industrial applications. [ABSTRACT FROM AUTHOR]