Elucidating the biosurfactant potential of Bacillus strains: a study of structure and function in food applications

This study explores the isolation and characterisation of biosurfactant-producing Bacillus strains. Four β-hemolytic isolates Bacillus velezensis (H6), Bacillus subtilis (S15 and S4), and Bacillus cereus (S32) were identified as potential biosurfactant producers. Among them, strain H6 showed the highest activity, reducing surface tension by 35 mN/m. This surface activity was further supported by FTIR analysis, which confirmed the lipopeptide nature of the compounds. In addition, thermogravimetric analysis indicated the thermal stability up to 140–190 °C. The biosurfactants also exhibited low critical micelle concentration values (0.3–0.5 g/L) outperformed sodium dodecyl sulphate and confirming their strong surface-active potential. Liquid chromatography–tandem mass spectrometry revealed diverse lipopeptide families, including surfactins, iturins, and fengycins, with strain H6 producing the highest levels. Overall, the biosurfactants displayed excellent functional properties, achieving up to 90% emulsification and foaming activity, which highlights their applicability in industrial sectors, particularly in food processing.本研究开展了产生物表面活性剂芽孢杆菌（Bacillus）菌株的分离与表征工作。共筛选鉴定出4株β溶血性芽孢杆菌作为潜在生物表面活性剂产生菌，分别为贝莱斯芽孢杆菌（Bacillus velezensis）H6、枯草芽孢杆菌（Bacillus subtilis）S15与S4，以及蜡样芽孢杆菌（Bacillus cereus）S32。其中菌株H6的表面活性最高，可将溶液表面张力降低35 mN/m。傅里叶变换红外光谱（FTIR）分析进一步验证了该活性，证实了所产活性物质的脂肽类属性。此外，热重分析结果表明，该生物表面活性剂的热稳定温度可达140–190 ℃。该类生物表面活性剂还表现出较低的临界胶束浓度（critical micelle concentration, CMC）值（0.3–0.5 g/L），其性能优于十二烷基硫酸钠（sodium dodecyl sulphate, SDS），证实了其优异的表面活性潜力。液相色谱-串联质谱（LC-MS/MS）分析显示，该类菌株可产生多种脂肽家族，包括表面活菌素（surfactins）、伊枯草菌素（iturins）与丰原素（fengycins），其中菌株H6的脂肽产量最高。总体而言，该生物表面活性剂展现出优异的功能特性，乳化活性与发泡活性最高可达90%，这凸显了其在工业领域尤其是食品加工中的应用价值。