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Elena Karpenko

Bio: Elena Karpenko is an academic researcher from National Academy of Sciences of Ukraine. The author has contributed to research in topics: Rhamnolipid & Micelle. The author has an hindex of 10, co-authored 23 publications receiving 452 citations.

Papers
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Journal ArticleDOI
TL;DR: Low critical micelle concentrations, tender action on nongrowing cells, and neutral effects on the growth of microbial strains at low surfactant concentrations make biosurfactant PS a potential candidate for application in different industrial fields, in environmental bioremediation, and in biomedicine.
Abstract: The potential of biosurfactant PS to permeabilize bacterial cells of Pseudomonas aeruginosa, Escherichia coli, and Bacillus subtilis on growing (in vivo) and resting (in vitro) cells was studied. Biosurfactant was shown to have a neutral or detrimental effect on the growth of Gram-positive strains, and this was dependent on the surfactant concentration. The growth of Gram-negative strains was not influenced by the presence of biosurfactant in the media. Cell permeabilization with biosurfactant PS was shown to be more effective with B. subtilis resting cells than with Pseudomonas aeruginosa. Scanning-electron microscopy observations showed that the biosurfactant PS did not exert a disruptive action on resting cells such that it was detrimental to the effect on growing cells of B. subtilis. Low critical micelle concentrations, tender action on nongrowing cells, and neutral effects on the growth of microbial strains at low surfactant concentrations make biosurfactant PS a potential candidate for application in different industrial fields, in environmental bioremediation, and in biomedicine.

183 citations

Journal ArticleDOI
TL;DR: The results indicate that rhamnolipid PS-17 and its alginate complex may be considered as promising substances for the development of anti-herpetic compounds.
Abstract: The rhamnolipid biosurfactant PS-17 and its complex with the polysaccharide alginate, both produced by the Pseudomonas sp. S-17 strain, were studied for their antiviral activity against herpes simplex virus (HSV) types 1 and 2. They significantly inhibited the herpesvirus cytopathic effect (CPE) in the Madin-Darby bovine kidney (MDBK) cell line. The investigations were carried out according to the CPE inhibition assay protocol. The suppressive effect of the compounds on HSV replication was dose-dependent and occurred at concentrations lower than the critical micelle concentration of the surfactant. The 50% inhibitory concentration (IC50) of rhamnolipid PS-17 was 14.5 microg/ml against HSV-1 and 13 microg/ml against HSV-2. The IC50 values of the complex were 435 microg/ml for HSV-1 and 482 microg/ml for HSV-2. The inhibitory effects of the substances were confirmed by measuring the infectious virus yields with the multicycle virus growth experimental design as well: deltalog CCID50 of 1.84-2.0 against the two types of herpes simplex viruses by rhamnolipid PS-17 (20 microg/ml), and a strong reduction of the HSV-2 virus yield under the effect of the alginate complex at a concentration of 450 microg/ml. The results indicate that rhamnolipid PS-17 and its alginate complex may be considered as promising substances for the development of anti-herpetic compounds.

57 citations

Journal ArticleDOI
TL;DR: The model equation may be used for controlling the biosynthesis of biosurfactants with properties targeted for specific applications, where generally the less pure the RL the higher the CMC.

50 citations

Journal ArticleDOI
TL;DR: It was found that the combination of rhamnolipid and thiosulfonic esters has a synergistic effect leading to decreasing of bactericidal and fungicidal concentrations of MTS and ETS.
Abstract: The antimicrobial properties of methyl (MTS) and ethyl (ETS) esters of thiosulfonic acid alone and in combination with rhamnolipid-biosurfactant (RL) have been characterized for their ability to disrupt the normal physiological functions of living pathogens. Bactericidal and fungicidal activities of MTS and ETS and their combination with rhamnolipid were demonstrated on strains of Pseudomonas aeruginosa, Bacillus subtilis, Alcaligenes faecalis, and Rhizopus ngtricans. It was found that the combination of rhamnolipid and thiosulfonic esters has a synergistic effect leading to decreasing of bactericidal and fungicidal concentrations of MTS and ETS. More extensively was studied the effect of rhamnolipid on the lipid composition of B. subtilis bacterial membrane. To our knowledge, in this article is reported for the first time a remarkable increase of negatively charged phospholipid cardiolipin in the presence of rhamnolipid. The capacity of RL as a surface-active substance was confirmed by scanning electron microscopy (SEM). The occurrence of surface infolds and blebs on B. subtilis shown by SEM, was not accompanied by changes in membrane permeability tested by a live/dead viability staining for fluorescence microscopy. When RL was applied in combination with MTS, a dramatic permeability shift for propidium iodide was observed in vegetative cells.

49 citations

Journal ArticleDOI
TL;DR: Experimental results showed the priority of resting bacterial cells in the biodegradation process over the growing cells, and the application of resting cells with high degrading activity as well as resting cells preliminary permeabilized with Triton X-100 based a new and effective approach for bioaugmentation and bioremediation of polluted with phenanthrene and with other polyaromatic hydrocarbons' soils and waters.

44 citations


Cited by
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Journal ArticleDOI
TL;DR: The current knowledge and the latest advances in biosurfactant applications and the biotechnological strategies being developed for improving production processes and future potential are reviewed.
Abstract: Microorganisms synthesise a wide range of surface-active compounds (SAC), generally called biosurfactants. These compounds are mainly classified according to their molecular weight, physico-chemical properties and mode of action. The low-molecular-weight SACs or biosurfactants reduce the surface tension at the air/water interfaces and the interfacial tension at oil/water interfaces, whereas the high-molecular-weight SACs, also called bioemulsifiers, are more effective in stabilising oil-in-water emulsions. Biosurfactants are attracting much interest due to their potential advantages over their synthetic counterparts in many fields spanning environmental, food, biomedical, and other industrial applications. Their large-scale application and production, however, are currently limited by the high cost of production and by limited understanding of their interactions with cells and with the abiotic environment. In this paper, we review the current knowledge and the latest advances in biosurfactant applications and the biotechnological strategies being developed for improving production processes and future potential.

1,248 citations

Journal ArticleDOI
TL;DR: It is evident from the literature survey presented herein that modified cellulose-based adsorbents exhibit good potential for the removal of various aquatic pollutants, however, still there is a need to find out the practical utility of these adsorbent on a commercial scale, leading to the improvement of pollution control.

747 citations

Journal ArticleDOI
TL;DR: A wide diversity of rhamnolipid congeners and homologues that are produced at different concentrations by various Pseudomonas species and by bacteria belonging to other families, classes, or even phyla are found.
Abstract: Rhamnolipids are glycolipidic biosurfactants produced by various bacterial species. They were initially found as exoproducts of the opportunistic pathogen Pseudomonas aeruginosa and described as a mixture of four congeners: α-L-rhamnopyranosyl-α-L-rhamnopyranosyl-β-hydroxydecanoyl-β-hydroxydecanoate (Rha-Rha-C10-C10), α-L-rhamnopyranosyl-α-L-rhamnopyranosyl-β-hydroxydecanoate (Rha-Rha-C10), as well as their mono-rhamnolipid congeners Rha-C10-C10 and Rha-C10. The development of more sensitive analytical techniques has lead to the further discovery of a wide diversity of rhamnolipid congeners and homologues (about 60) that are produced at different concentrations by various Pseudomonas species and by bacteria belonging to other families, classes, or even phyla. For example, various Burkholderia species have been shown to produce rhamnolipids that have longer alkyl chains than those produced by P. aeruginosa. In P. aeruginosa, three genes, carried on two distinct operons, code for the enzymes responsible for the final steps of rhamnolipid synthesis: one operon carries the rhlAB genes and the other rhlC. Genes highly similar to rhlA, rhlB, and rhlC have also been found in various Burkholderia species but grouped within one putative operon, and they have been shown to be required for rhamnolipid production as well. The exact physiological function of these secondary metabolites is still unclear. Most identified activities are derived from the surface activity, wetting ability, detergency, and other amphipathic-related properties of these molecules. Indeed, rhamnolipids promote the uptake and biodegradation of poorly soluble substrates, act as immune modulators and virulence factors, have antimicrobial activities, and are involved in surface motility and in bacterial biofilm development.

737 citations

Journal ArticleDOI
TL;DR: Positive results were found in basic studies of lowering the surface tension of water, of size determinations of micelles and vesicles, of emulsifying properties, biological activities, as well as of application tests in soil remediation.
Abstract: Low- and high-molecular-weight biosurfactants are of great interest because of their physicochemical and biological properties, which can be exploited in oil, food, cosmetic and pharmaceutical industries. As for the general types of microbial amphiphiles, the data accumulated over recent years are adding new interesting molecular structures to well-known compounds. Using new strains and cultivation conditions, positive results were found in basic studies of lowering the surface tension of water (72 mN/m→27 mN/m, cmc: 150 mg/l; rhamnose lipids from Pseudomonas aeruginosa ), of size determinations of micelles and vesicles (iturin A, a lipopeptide from Bacillus subtilis ), of emulsifying properties, biological activities, as well as of application tests in soil remediation.

321 citations

Journal ArticleDOI
TL;DR: This review highlights the relationships between biosurfactant molecular composition, structure, and their interfacial behavior and describes how environmental factors such as temperature, pH, and ionic strength can impact physicochemical properties and self-assembly behavior of biosurFactant-containing solutions and dispersions.

241 citations