Centre de Biotechnologie, Technopole Borj-Cedria, Hammam-Lif, Tunisia.
Biotechnol Prog. 2009 Sep-Oct;25(5):1267-74. doi: 10.1002/btpr.202.
An antimicrobial activity produced by Bacillus subtilis B38 was found to be effective against several bacteria, including pathogenic and spoilage microorganisms such as, Listeria monocytogenes, Salmonella enteridis, and clinical isolates of methicillin-resistant Staphylococcus species. Nutrients such as carbon, nitrogen sources, and inorganic salts enhanced the production level of the antibacterial activity by B. subtilis B38. A first screening step showed that lactose, ammonium succinate, and manganese most influenced both cell growth and antibacterial activity production. These three factors varied at two levels in eight experiments using full factorial design. Results indicated that maximum cell growth (OD = 10.2) and maximum production of antibacterial activity (360 AU/mL) were obtained in a modified medium containing 1.5% (w/v) lactose, 0.15% (w/v) ammonium succinate, and 0.3 mg/L manganese. Depending on the indicator strain used, the antibacterial activity was 2- to 4-fold higher in the modified culture medium than in TSB medium under the same conditions. Thin layer chromatography-bioautography assay showed the presence of three active spots with R(f) values of 0.47, 0.7, and 0.82 in TSB medium. However, the inhibition zone of two spots (R(f) values of 0.7 and 0.82) was slightly larger in the modified medium. Moreover, a large zone of inhibition with an R(f) value of 0.3, was observed in this modified medium, instead of the spot having an R(f) value of 0.47. These results suggest that the nutrients act as environmental factors, quantitatively and qualitatively affecting the production of antibacterial compounds by B. subtilis B38.
枯草芽孢杆菌 B38 产生的一种抗菌活性被发现对包括李斯特菌、肠炎沙门氏菌和耐甲氧西林金黄色葡萄球菌临床分离株在内的几种细菌有效。碳、氮源和无机盐等营养物质可提高枯草芽孢杆菌 B38 产生抗菌活性的水平。初步筛选表明，乳糖、琥珀酸铵和锰对细胞生长和抗菌活性的产生影响最大。在使用完全因子设计的八项实验中，这三个因素在两个水平上变化。结果表明，在含有 1.5%（w/v）乳糖、0.15%（w/v）琥珀酸铵和 0.3 mg/L 锰的改良培养基中可获得最大细胞生长（OD = 10.2）和最大抗菌活性（360 AU/mL）。根据所用指示菌株的不同，在改良培养基中的抗菌活性比在相同条件下的 TSB 培养基中高 2-4 倍。薄层层析-生物自显影试验表明，在 TSB 培养基中存在三个活性斑点，R(f) 值分别为 0.47、0.7 和 0.82。然而，在改良培养基中，两个斑点（R(f) 值为 0.7 和 0.82）的抑菌圈稍大。此外，在改良培养基中观察到一个 R(f) 值为 0.3 的大抑菌圈，而不是 R(f) 值为 0.47 的斑点。这些结果表明，营养物质作为环境因素，对枯草芽孢杆菌 B38 产生抗菌化合物的数量和质量产生影响。
