Congener-dependent conformations of isolated rhamnolipids at the vacuum-water interface: A molecular dynamics simulation

Euston, Stephen R.; Banat, İbrahim M.; Sałek, Karina

doi:10.1016/j.jcis.2020.11.082

Cited by 19 publications

(29 citation statements)

References 35 publications

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“…Such ability can be restored by extending the alkyl tail length . Euston et al also studied the surfactant conformation and their aggregation at the vacuum–water interfaces . Their conclusions on the influences of the H-bonding in the anionic form and the steric hindrance from the second rhamnose head are consistent with the findings of the Schwartz group .…”

Section: Introductionmentioning

confidence: 62%

“…This results in the aggregation of the ionic Rha-C10-C10 that grows inside the water solution, while the nonionic Rha-C10-C10 remains as a monolayer structure at the interface . The oil recovery ability is highly related to the micellar properties of the rhamnolipid solutions. − The relevant fundamental studies are mostly done by the Schwartz group using MD simulations. − Eismin et al found that Rha-C10-C10 can form micelles with 7–95 surfactant molecules. However, the initial structure of the aggregates obtained by the annealing process is found to be essential for observing the micellization within affordable computational time .…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the molecular modeling for rhamnolipids is still in its infancy. The current MD studies use CHARMM36 force field with a TIP3P water model or GROMOS with an SPCE water model . Although the force field has been validated against the micellization of sodium dodecyl sulfates (SDSs), the choice of the force field set and the parameterization with particular water models are known to yield diverse morphologies .…”

Section: Introductionmentioning

confidence: 99%

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Micellization of Rhamnolipid Biosurfactants and Their Applications in Oil Recovery: Insights from Mesoscale Simulations

Lee

2021

J. Phys. Chem. B

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The dissipative particle dynamics (DPD) mesoscopic method is used to investigate the self-assembly of rhamnolipid congeners and their aggregation behaviors with paraffins including nonane and pentadecane. The coarse-grained force field is parameterized by combining molecular dynamics (MD) simulations, COSMOtherm calculations, and available experimental data. This model reproduces the vesicular formation of α-L-rhamnopyranosylβ-hydroxydecanoyl-β-hydroxydecanoate (Rha-C10-C10) reported by all-atom MD simulations. The vesicle composed of Rha-C10-C10 is found to be most stable at a surfactant concentration of 100−146 mM based on asphericity analysis. The architecture of rhamnolipid congeners affects the morphology of their aggregates. Di-rhamno-di-lipidic dRha-C16-C16 forms vesicles with a thicker unilamellar layer of 3.2 nm. Rha-C16-C16 forms vesicles at a lower concentration of 70 mM, but the enclosed water space collapses when the surfactant concentration increases. dRha-C10-C10 forms wormlike micelles, which agglomerate into a torus and interconnected network at higher concentrations. In the presence of alkane molecules, dRha-C10-C10 maintains its wormlike micellar morphology with alkane molecules wrapped inside the aggregates. For Rha-C10-C10, Rha-C16-C16, and dRha-C16-C16, nonane molecules are distributed in the hydrophobic subdomain formed by rhamnolipid molecules. Spherical vesicles are formed at a surfactant concentration of 50 mM and then develop into ellipsoidal vesicles when the concentration increases to 125 mM. When mixed with pentadecane, the alkane molecules are aggregated and surrounded by surfactants forming a core−shell structure at a low surfactant concentration of 20 mM. At higher alkane and surfactant concentrations, the morphologies develop into disk micelles, wormlike micelles, and vesicles, with pentadecane molecules being distributed and packed with rhamnolipids. The obtained simulation results suggest that these biosurfactants have potential as environmental remediation agents.

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Section: Introductionmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Micellization of Rhamnolipid Biosurfactants and Their Applications in Oil Recovery: Insights from Mesoscale Simulations

Lee

2021

J. Phys. Chem. B

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“…This behaviour suggests that interactions within the RL congener and between molecules at the interface is complex and plays a significant role in their surface behaviour. Molecular dynamics simulations of RL congeners with differing chain length (C 14 C 14 , C 14 C 10 and C 10 C 14 ) also show differing properties of the congeners suggesting complex surface interactions within the molecule (Euston et al, 2021).…”

Section: Phase Behaviourmentioning

confidence: 99%

Phase Behaviour, Functionality, and Physicochemical Characteristics of Glycolipid Surfactants of Microbial Origin

Sałek

Euston

Janek

2022

Front. Bioeng. Biotechnol.

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Growing demand for biosurfactants as environmentally friendly counterparts of chemically derived surfactants enhances the extensive search for surface-active compounds of biological (microbial) origin. The understanding of the physicochemical properties of biosurfactants such as surface tension reduction, dispersion, emulsifying, foaming or micelle formation is essential for the successful application of biosurfactants in many branches of industry. Glycolipids, which belong to the class of low molecular weight surfactants are currently gaining a lot of interest for industrial applications. For this reason, we focus mainly on this class of biosurfactants with particular emphasis on rhamnolipids and sophorolipids, the most studied of the glycolipids.

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“…39 It was also demonstrated that nonionic and anionic aggregates present different stability and geometries over the water surface. 37,41 Moreover, it has been shown that Rha-C 10 -C 10 aggregates are stable in the presence of long chain alkanes in water and can be used to remove hydrocarbons from aqueous solutions. 38,40 Besides that, dirhamnolipid can generate bigger molecular aggregates than monorhamnolipid in n-alkanes solutions.…”

Section: Introductionmentioning

confidence: 99%

Automated Search For The Low-lying Energy Isomers of Rhamnolipids and Related Organometallic Complexes

Dobler

Oliveira

2022

Preprint

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Rhamnolipids (RMLs) are a widely studied biosurfactant due to its high biodegradability, low toxicity, and environmentally friendly production, which has the bacterium Pseudomonas aeruginosa as producer and renewable source of feedstock. However, the knowledge of the structure-property relationship of several RMLs congeners is imperative for the design of a high efficient application. Aiming to a better understanding of RMLs at a molecular level, we performed a automated search for low energy structures of the most abundant congeners, namely, Rha-C10, Rha-C10-C10, Rha-Rha-C10 and Rha-Rha-C10-C10 and their respective congener with two carbon atoms (C2) at the side chain. Besides that, selected neutral metal complexes were also considered. We thus performed a metadynamics search followed by DFT optimizations of selected geometries. In addition, molecular dynamics simulations were also applied. Our results show a plethora of low energy structures for each congener. Although several of them have internal hydrogen bonds, this interaction alone cannot explain the stability. Moreover, geometries in closed conformation were always more stable than ”open” ones and the effect of chain length on the geometry was found to be more prominent between Rha-Rha-C2-C2 and Rha-Rha-C10-C10 . Finally, the energy differences between open and closed conformations for K+ , Ni2+ , Cu2+ and Zn2+ complexes were found to be 23.5 kcal mol−1, 62.8 kcal mol−1 , 24.3 kcal mol−1 and 41.6 kcal mol−1 , respectively, indicating a huge structural reorganization after the complex formation.

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Congener-dependent conformations of isolated rhamnolipids at the vacuum-water interface: A molecular dynamics simulation

Cited by 19 publications

References 35 publications

Micellization of Rhamnolipid Biosurfactants and Their Applications in Oil Recovery: Insights from Mesoscale Simulations

Micellization of Rhamnolipid Biosurfactants and Their Applications in Oil Recovery: Insights from Mesoscale Simulations

Phase Behaviour, Functionality, and Physicochemical Characteristics of Glycolipid Surfactants of Microbial Origin

Automated Search For The Low-lying Energy Isomers of Rhamnolipids and Related Organometallic Complexes

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