IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga, Portugal.
Colloids Surf B Biointerfaces. 2010 Mar 1;76(1):298-304. doi: 10.1016/j.colsurfb.2009.11.008. Epub 2009 Dec 9.
In this study, the crude biosurfactant produced by a Lactobacillus paracasei strain isolated in a Portuguese dairy industry was characterized. The minimum surface tension (41.8mN/m) and the critical micelle concentration (2.5mg/ml) obtained were found to be similar to the values previously reported for biosurfactants isolated from other lactobacilli. The biosurfactant was found to be stable to pH changes over a range from 6 to 10, being more effective at pH 7, and showed no loss of surface activity after incubation at 60 degrees C for 120h. Although the biosurfactant chemical composition has not been determined yet, a fraction was isolated through acidic precipitation, which exhibited higher surface activity as compared with the crude biosurfactant. Furthermore, this isolated biosurfactant showed antimicrobial and anti-adhesive activities against several pathogenic microorganisms. In addition, L. paracasei exhibited a strong autoaggregating phenotype, which was maintained after washing and resuspending the cells in PBS, meaning that this attribute must be related to cell surface components and not to excreted factors. The autoaggregation ability exhibited by this strain, together with the antimicrobial and anti-adhesive properties observed for this biosurfactant opens the possibility for its use as an effective probiotic strain.
在这项研究中，对一株从葡萄牙乳制品工业中分离出来的副干酪乳杆菌所产生的原始生物表面活性剂进行了特性描述。研究发现，其最低表面张力（41.8mN/m）和临界胶束浓度（2.5mg/ml）与先前从其他乳杆菌分离出的生物表面活性剂的值相似。该生物表面活性剂在 pH 值为 6 到 10 的范围内变化时表现出稳定性，在 pH 值为 7 时效果最佳，并且在 60°C 孵育 120 小时后表面活性没有损失。虽然尚未确定生物表面活性剂的化学组成，但通过酸性沉淀分离出了一个馏分，该馏分的表面活性明显高于原始生物表面活性剂。此外，该分离出的生物表面活性剂对几种致病菌表现出抗菌和抗黏附活性。此外，副干酪乳杆菌表现出强烈的自聚集表型，即使在将细胞用 PBS 洗涤和重新悬浮后，该表型仍得以保持，这意味着该属性必须与细胞表面成分有关，而不是与分泌因子有关。该菌株所表现出的自动聚集能力，以及观察到的这种生物表面活性剂的抗菌和抗黏附特性，为其作为一种有效的益生菌菌株的应用提供了可能。
