The aim of present work was to study chemical structures and biological activities of rhamnolipid biosurfactants produced by Pseudomonas aeruginosa MN1 isolated from oil-contaminated soil. The results of liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis revealed that total rhamnolipids (RLs) contained 16 rhamnolipid homologues. Di-lipid RLs containing C(10)-C(10) moieties were by far the most predominant congeners among mono-rhamnose (53.29 %) and di-rhamnose (23.52 %) homologues. Mono-rhamnolipids form 68.35 % of the total congeners in the RLs. Two major fractions were revealed in the thin layer chromatogram of produced RLs which were then purified by column chromatography. The retardation factors (R (f)) of the two rhamnolipid purple spots were 0.71 for RL1 and 0.46 for RL2. LC-MS/MS analysis proved that RL1 was composed of mono-RLs and RL2 consisted of di-RLs. RL1 was more surface-active with the critical micelle concentration (CMC) value of 15 mg/L and the surface tension of 25 mN/m at CMC. The results of biological assay showed that RL1 is a more potent antibacterial agent than RL2. All methicillin-resistant Staphylococcus aureus (MRSA) strains were inhibited by RLs that were independent of their antibiotic susceptibility patterns. RLs remarkably enhanced the activity of oxacillin against MRSA strains and lowered the minimum inhibitory concentrations of oxacillin to the range of 3.12-6.25 μg/mL.

Department of Drug and Food Control and Biotechnology Research Center Faculty of Pharmacy Tehran University of Medical Sciences Tehran Iran

Zobrazit více v PubMed

J Microbiol Biotechnol. 2009 Feb;19(2):204-7 PubMed

Environ Pollut. 2005 Jan;133(2):183-98 PubMed

Appl Microbiol Biotechnol. 2007 Aug;76(1):67-74 PubMed

Folia Microbiol (Praha). 2011 Jul;56(4):297-303 PubMed

Appl Microbiol Biotechnol. 2010 May;86(5):1323-36 PubMed

Arch Pharm (Weinheim). 2008 Jan;341(1):42-8 PubMed

Daru. 2010;18(2):118-23 PubMed

J Microbiol Biotechnol. 2009 Dec;19(12):1576-81 PubMed

Appl Microbiol Biotechnol. 1999 Aug;52(2):154-62 PubMed

Clin Microbiol Infect. 2005 May;11 Suppl 3:22-8 PubMed

J Chromatogr A. 1999 Dec 24;864(2):211-20 PubMed

Biochim Biophys Acta. 1999 Sep 22;1440(2-3):244-52 PubMed

Appl Microbiol Biotechnol. 2000 Nov;54(5):625-33 PubMed

Biotechnol Bioeng. 2003 Feb 5;81(3):316-22 PubMed

Arch Pharm (Weinheim). 2009 Jul;342(7):405-11 PubMed

Adv Colloid Interface Sci. 2007 Oct 31;134-135:24-34 PubMed

Eur J Med Chem. 2011 Jan;46(1):65-70 PubMed

Curr Microbiol. 2008 Jun;56(6):639-44 PubMed

Microbiol Res. 2001 Mar;155(4):249-56 PubMed

Appl Environ Microbiol. 2005 Sep;71(9):5171-6 PubMed

Biochim Biophys Acta. 2000 May 31;1485(2-3):145-52 PubMed

Microbiol Mol Biol Rev. 1997 Mar;61(1):47-64 PubMed

J Microbiol Methods. 2004 Mar;56(3):339-47 PubMed

Biotechnol Prog. 2005 Nov-Dec;21(6):1593-600 PubMed

Bioorg Med Chem. 2004 Feb 1;12(3):583-7 PubMed

Appl Microbiol Biotechnol. 1999 Jan;51(1):22-32 PubMed

Colloids Surf B Biointerfaces. 2010 Dec 1;81(2):397-405 PubMed

Curr Microbiol. 2010 Apr;60(4):237-41 PubMed

Biotechnol Bioeng. 1989 Jan 15;33(3):365-8 PubMed

FEMS Microbiol Lett. 1999 Aug 1;177(1):57-62 PubMed

Biol Pharm Bull. 2004 Jul;27(7):1116-20 PubMed

Folia Microbiol (Praha). 2010 Sep;55(5):497-501 PubMed

Pharm Acta Helv. 1991;66(9-10):274-80 PubMed

Biochim Biophys Acta. 1990 Jul 16;1045(2):189-93 PubMed

Cobalt Bis-Dicarbollide Enhances Antibiotics Action towards Staphylococcus epidermidis Planktonic Growth Due to Cell Envelopes Disruption