title: Comparison of biosurfactant detection methods reveals hydrophobic surfactants and contact-regulated production.
abstract: 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.
authors: Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
authors: Adrien Y
authors: AY
authors: Burch
authors: Patrick J
authors: PJ
authors: Browne
authors: Christopher A
authors: CA
authors: Dunlap
authors: Neil P
authors: NP
authors: Price
authors: Steven E
authors: SE
authors: Lindow
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001431:Bacteriological Techniques / Q000379:methods*; D003470:Culture Media; D057166:High-Throughput Screening Assays / Q000379:methods; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D009821:Oils; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013500:Surface Tension; D013501:Surface-Active Agents / Q000302:isolation & purification* / Q000378:metabolism; D014871:Water Microbiology
chemical_list: D003470:Culture Media; D009821:Oils; D012336:RNA, Ribosomal, 16S; D013501:Surface-Active Agents