title: Antibacterial properties of biosurfactants against selected Gram-positive and -negative bacteria.
abstract: The antibacterial properties and ability to disrupt biofilms of biosurfactants (rhamnolipids, sophorolipids) and sodium dodecyl sulphate (SDS) in the presence and absence of selected organic acids were investigated. Pseudomonas aeruginosa PAO1 was inhibited by sophorolipids and SDS at concentrations >5% v/v, and the growth of Escherichia coli NCTC 10418 was also inhibited by sophorolipids and SDS at concentrations >5% and 0.1% v/v, respectively. Bacillus subtilis NCTC 10400 was inhibited by rhamnolipids, sophorolipids and SDS at concentrations >0.5% v/v of all three; the same effect was observed with Staphylococcus aureus ATCC 9144. The ability to attach to surfaces and biofilm formation of P. aeruginosa PAO1, E. coli NCTC 10418 and B. subtilis NCTC 10400 was inhibited by sophorolipids (1% v/v) in the presence of caprylic acid (0.8% v/v). In the case of S. aureus ATCC 9144, the best results were obtained using caprylic acid on its own. It was concluded that sophorolipids are promising compounds for the inhibition/disruption of biofilms formed by Gram-positive and Gram-negative microorganisms and this activity can be enhanced by the presence of booster compounds such as caprylic acid.
authors.affiliation: School of Chemical Engineering and Analytical Science, University of Manchester, Manchester, M13 9PL, UK.
authors.forename: Mayri A
authors.initials: MA
authors.lastname: Díaz De Rienzo
authors.affiliation: Unilever Research and Development Laboratory, Port Sunlight, Wirral, CH62 4ZD, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Stevenson
authors.affiliation: School of Biomedical Sciences, University of Ulster, Coleraine, BT52 1SA, Northern Ireland, UK.
authors.forename: Roger
authors.initials: R
authors.lastname: Marchant
authors.affiliation: School of Biomedical Sciences, University of Ulster, Coleraine, BT52 1SA, Northern Ireland, UK IM.Banat@ulster.ac.uk.
authors.forename: Ibrahim M
authors.initials: IM
authors.lastname: Banat
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D008826:Microbial Sensitivity Tests; D013501:Surface-Active Agents / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D013501:Surface-Active Agents
keywords: antimicrobial; biofilms; biosurfactants; rhamnolipids; sophorolipids