Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
Environ Microbiol. 2011 Oct;13(10):2681-91. doi: 10.1111/j.1462-2920.2011.02534.x. Epub 2011 Aug 30.
Biosurfactants are diverse molecules with numerous biological functions and industrial applications. A variety of environments were examined for biosurfactant-producing bacteria including soil, water and leaf surfaces. Biosurfactant production was assessed with an atomized oil assay for a large number of bacterial isolates and compared with a commonly used drop collapse assay from broth and plate cultures. The atomized oil assay detected every strain that produced a biosurfactant detectable by the drop collapse test, and also identified additional strains that were not detected with the drop collapse assay because they produced low levels of surfactant or hydrophobic (low water solubility) surfactants such as pumilacidins. Not all strains that produced a biosurfactant detectable by the drop collapse when cultured on agar surfaces produced surfactants detectable by drop collapse when cultured in broth, and vice versa. Many bacterial strains exhibited preferential production of surfactants when grown on an agar surface compared with broth cultures, and such surface enhancement of production could also be stimulated by increasing the viscosity of liquid culture media. Surface induction of surfactant production in the epiphyte Pseudomonas syringae was regulated at the transcriptional level.
生物表面活性剂是具有多种生物学功能和工业应用的多样化分子。研究了包括土壤、水和叶片表面在内的各种环境中的产生物表面活性剂的细菌。通过雾化油分析对大量细菌分离株进行了生物表面活性剂的生产评估，并与来自液体培养物的平板和肉汤培养的常用滴崩溃分析进行了比较。雾化油分析检测到了用滴崩溃测试可检测到生物表面活性剂的每一种菌株，并且还鉴定出了其他未用滴崩溃测试检测到的菌株，因为它们产生的表面活性剂水平较低或疏水性（低水溶性）表面活性剂，如 pumilacidins。并非所有在琼脂表面上培养时用滴崩溃法可检测到生物表面活性剂的菌株在液体培养物中用滴崩溃法可检测到表面活性剂，反之亦然。与液体培养物相比，许多细菌菌株在琼脂表面上生长时更倾向于产生表面活性剂，并且液体培养基的粘度增加也可以刺激这种表面生产的增强。在附生菌丁香假单胞菌中，表面诱导的表面活性剂生产在转录水平上受到调节。
