The use of small angle neutron scattering, SANS, neutron reflectivity, NR, and surface tension to study the mixing properties of the biosurfactant rhamnolipid with a conventional anionic surfactant, sodium dodecyl 6-benzene sulfonate, LAS, is reported. The monorhamnose rhamnolipid, R1, mixes close to ideally with LAS at the air-water interface, whereas for mixtures of LAS with the dirhamnose rh...

Water-immiscible substrate, diesel, was supplied as the main substrate in the fermentation of Pseudomonas aeruginosa USM-AR2 producing rhamnolipid biosurfactant, in a stirred tank bioreactor. In addition to the typical gas-aqueous system, this system includes gas-hydrocarbon-aqueous phases and the presence of surfactant (rhamnolipid) in the fermentation broth. The effect of diesel dispersion on...

In this study one hundred and fifty two bacterial strains were isolated from oil contaminated. Hemolysis was used as a criterion for the primary isolation of biosurfactant producing-bacteria. Fifty five strains had haemolytic activity, among them twelve strains were good biosurfactant producers by measuring surface tension and emulsification activity. Two microorganisms showed the highest biosu...

Biosurfactants are structurally diverse surface-active agents mostly produced by various genera of bacteria, yeast and filamentous fungi that have a wide range applications properties. They surface interfacial activity, temperature pH tolerance, biodegradability, low toxicity anti-adhesive property. Their production was reported to be affected temperature, PH, aeration agitation, salt concentra...

P. aeruginosa M14808 was screened to produce rhamnolipid with high yield by mutation in a high magneto-gravitational environment. After silica gel columniation chromatogram, the components of the crude biosurfactant extract were analyzed by TLC, FTIR, and ESI-MS. The major components were characterized as rhamnolipids. The rhamnolipids consisted of two main types, monoand di-rhamnolipids. Di-rh...

The Pseudomonas aeruginosa rhlAB operon encodes the enzyme rhamnosyltransferase 1, which produces the biosurfactant mono-rhamnolipid; rhlAB induction is dependent on the quorum-sensing transcription activator RhlR complexed with the autoinducer N-butyryl-homoserine lactone (C(4)-HSL). In this work we studied rhlAB induction in a P. aeruginosa and Escherichia coli background. We found that, in b...

Biosynthesis of biosurfactant rhamnolipids by Pseudomonas aeruginosa depends on two hierarchical quorum sensing systems, LasRI and RhlRI, which synthesize and sense the signal molecules N-(3-oxododecanoyl)-L-homoserine lactone (3OC₁₂-HSL) and N-butyryl-L-homoserine lactone (C₄-HSL), respectively. The Pseudomonas Quinolone Signal (PQS) is a third cell-to-cell signal molecule connecting these two...

Experiments were conducted with a two-dimensional flow cell to examine the effect of monorhamnolipid surfactant at sub-CMC concentrations on solubilization of dodecane in porous media under dynamic flow conditions. Quartz sand was used as the porous medium and artificial groundwater was used as the background solution. The effectiveness of the monorhamnolipid was compared to that of SDBS, Trito...