Rhamnolipids are conserved biosurfactants molecules: implications for their biotechnological potential
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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.
KeywordsRhamnolipids Biosurfactants Pseudomonas aeruginosa Bioreactor Comparative gene analysis Gene expression
We thank Prof James Dooley at the University of Ulster for providing the clinical strains used in this study. A.P. is grateful to Dr. Urs Ochsner for his valuable advice at the beginning of this study. This work was supported by Unilever and the Department of Trade and Industry technology programme and a CAST award from the Department of Education and Learning Northern Ireland and Unilever to Michelle Rudden.
- Betts MJ, Russel RB (2003) Amino acid properties and consequences of substitutions. In: Barnes MR, Gray IC (eds) Bioinformatics for geneticists. Wiley-Interscience, New YorkGoogle Scholar
- Chen ML, Penfold J, Thomas RK, Smyth TJP, Perfumo A, Marchant R, Banat IM, Stevenson P, Parry A, Tucker I, Grillo I (2010a) Mixing behavior of the biosurfactant, rhamnolipid, with a conventional anionic surfactant, sodium dodecyl benzene sulfonate. Langmuir 26:17958–17968PubMedCrossRefGoogle Scholar
- Chen ML, Penfold J, Thomas RK, Smyth TJP, Perfumo A, Marchant R, Banat IM, Stevenson P, Parry A, Tucker I, Grillo I (2010b) Solution self-assembly and adsorption at the air-water interface of the monorhamnose and dirhamnose rhamnolipids and their mixtures. Langmuir 26:18281–18292PubMedCrossRefGoogle Scholar
- Chandrasekaran EV, Bemiller JN (1980) Constituent analysis of glycosaminoglycans. In: Whistler RL (ed) Methods in carbohydrate chemistry. Academic, New York, pp 89–96Google Scholar
- Déziel E, Lépine F, Milot S, Villemur R (2000) Mass spectrometry monitoring of rhamnolipids from a growing culture of Pseudomonas aeruginosa 57RP. Biochim Biophys Acta 31:145–152Google Scholar
- Fracchia L, Cavallo M, Martinotti MG, Banat IM (2012) Biosurfactants and bioemulsifiers biomedical and related applications—present status and future potentials. In: Ghista DN (ed) Biomedical science, engineering and technology, pp 325–370Google Scholar
- Makkar RS, Cameotra SS, Banat IM (2011) Advances in utilization of renewable substrates for biosurfactant production. Appl Microbiol Biotechnol Express 1(1):1–5Google Scholar
- Smyth TJP, Perfumo A, Marchant R, Banat IM (2010) Isolation and analysis of low molecular weight microbial glycolipids, vol. 5, part 2. In: KN Timmis (ed) Handbook of hydrocarbon and lipid microbiology. Springer, Berlin, pp 3705–3723Google Scholar
- Stover CK, Pham XQ, Erwin AL, Mizoguchi SD, Warrener P, Hickey MJ, Brinkman FS, Hufnagle WO, Kowalik DJ, Lagrou M, Garber RL, Goltry L, Tolentino E, Westbrock-Wadman S, Yuan Y, Brody LL, Coulter SN, Folger KR, Kas A, Larbig K, Lim R, Smith K, Spencer D, Wong GK, Wu Z, Paulsen IT, Reizer J, Saier MH, Hancock RE, Lory S, Olson MV (2000) Complete genome sequence of Pseudomonas aeruginosa PAO1, an opportunistic pathogen. Nature 406:959–964PubMedCrossRefGoogle Scholar
- Zhu H, Bandara R, Conibear TCR, Thuruthyil SJ, Rice SA, Kjelleberg S, Givskov M, Willcox MDP (2004) Pseudomonas aeruginosa with LasI quorum-sensing deficiency during corneal infection. IOVS 45:1897–1903Google Scholar