This study aimed to investigate the antimicrobial, antibiofilm, and cytotoxic effects of biosurfactant lipopeptides synthesized by Bacillus subtilis TR47II. For this purpose, the lipopeptides were partially purified using a three-step process and characterized. In the first step, the crude extract obtained from acid precipitation exhibited strong antibacterial activity against the Gram-negative opportunistic pathogens Alcaligenes faecalis ATCC 8750, Achromobacter xylosoxidans ATCC 13138, Pseudomonas alcaligenes ATCC 14909, and Pseudomonas putida ATCC 15175. Moreover, partial inhibition was observed against Klebsiella aerogenes ATCC 13048 (42%), Escherichia coli ATCC 25922 (16%), and Pseudomonas aeruginosa ATCC 27853 (47%). The lipopeptides in the crude extract were extracted with methanol and fractioned on a silica gel chromatography column, rendering four TLC-pooled chromatographic fractions, named F1, F2, F3, and F4. The chromatographic fraction F4 was the most bioactive, with MIC values between 300 and 600 µg mL⁻¹. Besides, F4 at sub-MIC doses dislodged the biofilms of A. faecalis, A. xylosoxidans, and P. alcaligenes by about 100, 85, and 81%, respectively. No cytotoxic effect was observed in mammalian cells at MIC. MALDI-TOF-MS analysis revealed that F4 contained cyclic lipopeptides belonging to two families: iturins (m/z 1004 to 1087) and fengycins (m/z 1424 to 1545). The dual effect of F4 on planktonic and sessile growth could suggest that the synergistic application of these biosurfactants could be efficient in the control of these opportunistic pathogens.

这项研究旨在调查枯草芽孢杆菌TR47II合成的生物表面活性剂脂肽的抗微生物，抗生物膜和细胞毒性作用。为此目的，使用三步法部分纯化脂肽并进行表征。在第一步中，从酸沉淀中获得的粗提物对革兰氏阴性致病菌粪便产碱杆菌ATCC 8750，木糖氧化无色杆菌ATCC 13138，产碱假单胞菌ATCC 14909和恶臭假单胞菌ATCC 15175表现出较强的抗菌活性。此外，还观察到部分抑制作用。对抗产气克雷伯氏菌ATCC 13048（42％），大肠杆菌ATCC 25922（16％）和铜绿假单胞菌ATCC 27853（47％）。用甲醇萃取粗提物中的脂肽，并在硅胶色谱柱上进行分馏，得到四个TLC合并的色谱级分，称为F1，F2，F3和F4。色谱馏分F4具有最高的生物活性，MIC值为300至600 µg mL ^-1。此外，F4在亚MIC剂量脱落的生物膜粪，A.木糖氧化和产碱假单胞菌分别减少约100％，85％和81％。在MIC下在哺乳动物细胞中未观察到细胞毒性作用。MALDI-TOF-MS分析显示，F4包含属于两个家族的环状脂肽：伊图林（m / z 1004至1087）和丰霉素（m / z 1424至1545）。F4对浮游和无柄生长的双重影响可能表明，这些生物表面活性剂的协同应用可能有效控制这些机会病原体。