en Other Other Original Article Original Article <p><span style="font-size:12px;"><span style="font-family:Tahoma;"><span style="line-height:14.0pt">Natural products recovered from marine sediment have the potential for the treatment of various diseases. <i>Streptomyces</i> sp., strain MN38 which was previously isolated from the Caspian Sea of Iran was at first characterized based on its 16srRNA analysis and morphological properties. Two-factor Interaction/ Minimum Run Resolution IV method was employed to evaluate the influence of various potential factors on the strain&#39;s antibacterial activity using cost-effective substrates.</span><br> <span style="line-height:14.0pt">Twelve variables were considered effective for investigation, with an emphasis on assessing the antibacterial activity against <i>Staphylococcus aureus</i> and <i>Enterococcus faecalis</i> via the micro-dilution method. The findings indicate that a quadratic model and a second-order polynomial equation are statistically significant at the 95% confidence level due to a low P-value (< 0.0001) in this context. </span><br> <span style="line-height:14.0pt">As a result, A1BFe+C agar medium, incubated at 28&deg;C for three days with a shaking speed of 200 rpm, using specific concentrations of starch (5.0 g/l), yeast extract (6.0 g/l), peptone (4.0 g/l), KBr (0.5 g/l), CaCO₃ (0.2 g/l), sea salt (15 g/l), and Fe₂(SO₄)₃ (0.003 g/l), along with an inoculum size of 3.0% v/v at a pH of 6, exhibits the enhanced antibacterial activity against <i>Staphylococcus aureus</i> and <i>Enterococcus faecalis</i> reached up to 69 and 166 (Bu/ml). It could be concluded that the MN38 of Caspian Sea sediments was a potent source of antimicrobial agent production and the production process was significantly optimized using mathematical methods.</span></span></span></p> <br> &nbsp; Caspian Sea, Marine Streptomyces optimization, antibacterial activity, 2FI/ Min Run Res IV, 666 681 http://ijmcmed.org/browse.php?a_code=A-10-1352-2&slc_lang=en&sid=1 Zeinab Jan JanZ971@mums.ac.ir 100319475328460034458 100319475328460034458 No Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran Hamed Norouzi Taheri hamed.nt68@yahoo.com 100319475328460034459 100319475328460034459 No 3. Department of Biology Education, Farhangian University, Tehran, Iran Abolghasem Danesh DaneshA@mums.ac.ir 100319475328460034460 100319475328460034460 Yes Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran