Pak J Biol Sci. 2022 Jun;25(7):642-653. doi: 10.3923/pjbs.2022.642.653.
<b>Background and Objective:</b> Actinobacteria represent the most prominent group of microorganisms, which produce a vast number of bioactive compounds especially antibiotics. The present study investigated the antibacterial activity of some actinomycete isolates against <i>Ralstonia solanacearum</i> type 3 biovar 2 (phytopathogenic bacterium that causes tomato wilt disease and brown rot of potatoes). <b>Materials and Methods:</b> The most potent actinomycete isolates in the antibacterial activity was further identified up to species based on its phenotypic and molecular characteristics. Additionally, the most suitable carbon and nitrogen sources for increasing the antibacterial activity were also investigated. <b>Results:</b> Interestingly, <i>Streptomyces </i>isolate MSQ21 achieved the highest antibacterial activity against <i>R. solanacearum</i> with an inhibition zone of 18 mm. 16S rRNA gene analysis suggested that <i>Streptomyces </i>MSQ21 was identified as a strain of <i>S. maritimus</i> Glycerol (2.25%, w/v) and (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> (0.13%, w/v) were the most suitable carbon and nitrogen sources for increasing the antibacterial activity. <b>Conclusion:</b> It could be concluded that the maximum antibacterial activity (30mm) produced by <i>S. maritimus </i>strain MSQ21 against <i>R. solanacearum </i>could be obtained by using the modified starch nitrate medium containing (g L<sup>1</sup>): Glycerol, 25: Ammonium sulphate, 1.6: Dipotassium hydrogen phosphate, 1: Magnesium sulphate, 0.5: Sodium chloride, 0.5: Calcium carbonate, 3: Ferrous sulphate and 0.01: Distilled water up to 1 L and under the following conditions: Temperature 30°C, agitation speed 250 rpm, inoculum size 1-50 mL medium, incubation period 4 days and pH 8.5.
背景与目的：放线菌是产生大量生物活性化合物（尤其是抗生素）的最主要微生物群。本研究调查了一些放线菌分离物对 3 型 2 生物变种（引起番茄萎蔫病和马铃薯褐腐病的植物病原菌）的抗菌活性。
材料与方法：根据表型和分子特征，对具有最强抗菌活性的放线菌分离物进行了进一步鉴定，直至种的水平。此外，还研究了增加抗菌活性的最佳碳源和氮源。
结果：有趣的是，分离物 MSQ21 对 <i>R. solanacearum</i>的抗菌活性最高，抑菌圈为 18mm。16S rRNA 基因分析表明，<i>Streptomyces </i>MSQ21 被鉴定为 <i>S. maritimus</i>菌株。甘油（2.25%，w/v）和（NH<sub>4</sub>）<sub>2</sub>SO<sub>4</sub>（0.13%，w/v）是增加抗菌活性的最佳碳源和氮源。
结论：可以得出结论，<i>S. maritimus </i>MSQ21 菌株对 <i>R. solanacearum </i>的最大抗菌活性（30mm）可通过使用改良的淀粉硝酸盐培养基获得，其中含有（gL<sup>1</sup>）：甘油 25：硫酸铵 1.6：磷酸二氢钾 1：硫酸镁 0.5：氯化钠 0.5：碳酸钙 3：硫酸亚铁 0.01：蒸馏水至 1L，并在以下条件下：温度 30°C，搅拌速度 250rpm，接种量 1-50mL 培养基，培养时间 4 天，pH8.5。
