Rhamnolipids

A (1 — SO-coupled compound between methyl (3/ )-3-[(3 / )-3 -hydroxy-decanoyloxy]decanoate and 2-0-a-L-rhamnopyranosyl-o -L-rhamnopyra-nose, a rhamnolipid from Pseudomonas aeruginosa, expected to have various biological activities, was prepared by double couplings using 3,4-di-0-benzyl-2-0-chloroacetyl-a-L-rhamnopyranosyl fluoride (by the BFj- OEtj method). 

Itoh S, T Suzuki (1972) Effect of rhamnolipids on growth of Pseudomonas aeruginosa mutant deficient in -paraffin-utilizing ability. Agric Biol Chem 36 2233-2235. 

Rendell NB, GW Taylor, M Somerville, H Todd, R Wilson, PJ Cole (1990) Characterization of Pseudomonas rhamnolipids. Biochim Biophys Acta 1045 189-193. 

Zhang Y, WJ Maier, RM Miller (1997) Effect of rhamnolipids on the dissolution, bioavailability and biodegradation of phenanthrene. Environ Sci Technol 31 2211-2217. 

Increased removal of phenanthrene from soil columns spiked with the rhamnolipid mixture synthesized by Pseudomonas aeruginosa UG2 has been demonstrated, and shown to depend both on the increased desorption of the substrate and on partitioning into micelles (Noordman et al. 1998). However, the addition of the biosurfactant from the same strain of Pseudomonas aeruginosa UG2 or of sodium dodecyl sulfate had no effect on the rate of biodegradation of anthracene and phenanthrene from a chronically contaminated soil. 

The addition of a rhamnolipid biosurfactant produced by Pseudomonas aeruginosa stain ATIO apparently reduced the extent of degradation by endogenous bacteria of benz[fl]anthracene and chrysene in a creosote-contaminated soil (Vinas et al. 2005). 

Arino S, R Marchal, J-P Vandecasteele (1998) Involvement of a rhamnolipid-producing strain of Pseudomonas aeruginosa in the degradation of polycyclic aromatic hydrocarbons by a bacterial community. J Appl Microbiol 84 769-776. 

Noordman WH, W Ji, ML Briusseau, DB Janssen (1998) Effects of rhamnolipid biosurfactants on removal of phenanthrene from soil. Environ Sci Technol 32 1806-1812. 

Sandrin, T.R., Chech, A.M., and Maier, R.M., A rhamnolipid biosurfactant reduces cadmium toxicity during naphthalene biodegradation, Appl Environ Microbiol, 66 (10), 4585-4588, 2000. 

Maslin, P. and Maier, R.M., Rhamnolipid-enhanced mineralization of phenanthrene in organic-metal co-contaminated soils, Bioremediat J, 4 (4), 295-308, 2000. 

The alkane rc-tetradecane was found to have significant effect on desulfurization ability, with the rate being 10 times more than that obtained when using glucose for biocatalyst growth. This effect was associated with production of rhamnolipids by the strain. However, the mechanism by which alkane actually enhances desulfurization activity, whether it is by assisting in biosurfactant production or by some other mechanism was not reported. However, this biocatalyst was found to be active for only a short period (4h) during its desulfurization test with oils. 

Figure 3. Ionic biosurfactant rhamnolipid, Ri, R2 = C5H11, C7H15 or C9H19...

Noordman, W. H. and Janssen, D. B. (2002). Rhamnolipid stimulates uptake of hydrophobic compounds by Pseudomonas aeruginosa, Appl. Environ. Microbiol., 68, 4502-4508. 

Beal, R. and Betts, W. B. (2000). Role of rhamnolipid biosurfactants in the uptake and mineralization of hexadecane in Pseudomonas aeruginosa, J. Appl. Microbiol., 89, 158-168. 

Churchill, S. A., Griffin, R. A., Jones, L. P. Churchill, P. F. (1995). Biodegradation rate enhancement of hydrocarbons by an oleophilic fertilizer and a rhamnolipid biosurfactant. Journal of Environmental Quality, 24, 19—28. 

Hisatsuka, K., Nakahara, T., Sano, N. Yamada, K. (1971). Formation of rhamnolipid by Pseudomonas aeruginosa and its function in hydrocarbon fermentation. Agricultural and Biological Chemistry, 35, 686. 

Zhang, Y. Miller, R. M. (1992). Enhanced octadecane dispersion and biodegradation by a Pseudomonas rhamnolipid surfactant (biosurfactant). Applied and Environmental Microbiology, 58, 3276-82. 

Figure 10.1. (a) Rhamnolipid from P. aeruginosa ATCC 9027 showing cadmium binding, (b) Structure of the iron-siderophore complex of enterobactin. 

Champion, J. T., Gilkey, J. C., Lamparski, H., Rettner, J. Miller, R. M. (1995). Electron microscopy of rhamnolipid (biosurfactant) morphology effects of pH, cadmium and octadecant. Journal of Colloid and Interface Science, 170, 569-74. 

Herman, D.C., Artiola, J.F. Miller, R. M. (1995). Removal of cadmium, lead, and zinc from soil by a rhamnolipid biosurfactant. Environmental Science andTechnology, 29,2280-5. 

Zhang, Y. Miller, R.M. (1995). Effect of rhamnolipid (biosurfactant) structure on solubilization and biodegradation of n-alkanes. Applied and Environmental Microbiology, 61, 2247-51. 

The autoinducer of the third quorum sensing system in P. aeruginosa is PQS. (Figure 36) PQS is involved in lasB expression, and RhlR is required for PQS activity. The structure of PQS is similar to that of antimicrobial quinolones, but PQS shows no antimicrobial activity. PQS is converted from 2-heptyl-4(lH)-quinolone (HHQ) by PqsH, which is activated by 3-oxo-Cl2-HSL—LasR. PQS regulates the expression of elastase, rhamnolipid, pyocyanin, and LecA. As PQS regulates LasB expression and the synthesis of PQS is regulated by LasR and... 

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