title: Rhamnolipids are conserved biosurfactants molecules: implications for their biotechnological potential.
abstract: A range of isolates of Pseudomonas aeruginosa from widely different environmental sources were examined for their ability to synthesise rhamnolipid biosurfactants. No significant differences in the quantity or composition of the rhamnolipid congeners could be produced by manipulating the growth conditions. Sequences for the rhamnolipid genes indicated low levels of strain variation, and the majority of polymorphisms did lead to amino acid sequence changes that had no evident phenotypic effect. Expression of the rhlB and rhlC rhamnosyltransferase genes showed a fixed sequential expression pattern during growth, and no significant up-regulation could be induced by varying producer strains or growth media. The results indicated that rhamnolipids are highly conserved molecules and that their gene expression has a rather stringent control. This leaves little opportunity to manipulate and greatly increase the yield of rhamnolipids from strains of P. aeruginosa for biotechnological applications.
authors.affiliation: School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, UK.
authors.forename: Amedea
authors.initials: A
authors.lastname: Perfumo
authors.forename: Michelle
authors.initials: M
authors.lastname: Rudden
authors.forename: Thomas J P
authors.initials: TJ
authors.lastname: Smyth
authors.forename: Roger
authors.initials: R
authors.lastname: Marchant
authors.forename: Paul S
authors.initials: PS
authors.lastname: Stevenson
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Parry
authors.forename: Ibrahim M
authors.initials: IM
authors.lastname: Banat
mesh_terms: D053898:Biosynthetic Pathways / Q000235:genetics*; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004783:Environmental Microbiology; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006017:Glycolipids / Q000096:biosynthesis*; D006801:Humans; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D011552:Pseudomonas Infections / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013501:Surface-Active Agents / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D006017:Glycolipids; D013501:Surface-Active Agents; C418382:rhamnolipid