Production and characterization of rhamnolipids from Pseudomonas aeruginosa san ai

Production and characterization of rhamnolipid biosurfactant obtained by strain Pseudomonas aeruginosa san ai was investigated. With regard to carbon and nitrogen source several media were tested to enhance production of rhamnolipids. Phosphate-limited proteose peptone-ammonium salt (PPAS) medium supplemented with sun flower oil as a source of carbon and mineral ammonium chloride and peptone as a nitrogen source greatly improved rhamnolipid production, from 0.15 on basic PPAS (C/N ratio 4.0), to 3 g L-1, on optimized PPAS medium (C/N ratio 7.7). Response surface methodology analysis was used for testing effect of three factors: temperature, concentration of carbon and nitrogen source (w/w), in optimized PPAS medium on rhamnolipid production. Isolated rhamnolipids were characterized by IR and ESI-MS. IR spectra confirmed that isolated compound corresponds to rhamnolipid structure, whereas MS indicated that isolated preparation is a mixture of mono-rhamno-mono-lipidic, mono-rhamno-di-lipidic- and dirhamno- di-lipidic congeners

Моделирование кинетики прямого амидирования жирных кислот диэтаноламином

BACKGROUND: , Aims and Scope. In oil spill investigations, one of the most important steps is a proper choice of approaches that imply an investigation of samples taken from different sedimentary environments, samples of oil contaminants taken in different periods of time and samples taken at different distances from the oil spill. In all these cases, conclusion on the influence of the environment, microorganisms or migration on the oil contaminants' composition can be drawn from the comparison of chemical compositions of the investigated contaminants. However, in case of water contaminants, it is very important to define which part of organic matter has been analyzed. Namely, previous investigations showed that there were some differences in chemical composition of the same oil contaminant depending on the intensity of its contact with ground water. The aim of this work is to define more precisely the interactions between oil contaminant and water, i.e. the influence of the intensity of interaction between the oil contaminant and water on its chemical composition. The study was based on a comparison of four fractionated extracts of an oil pollutant, after they had been analyzed in details. Methods. Oil polluted surface water (wastewater canal, Pancevo, Serbia) was investigated. The study was based on a comparison of four extracts of an oil contaminant: extract I (decanted part), and extracts 2, 3 and 4 (extracted by shaking for 1 minute, 5 minutes and 24 hours, respectively). The fractionated extracts were saponified with a solution of KOH in methanol, and neutralized with 10% hydrochloric acid. The products were dissolved in a mixture of dichloromethane and hexane, and individually fractionated by column chromatography on alumina and silica gel (saturated hydrocarbon, aromatic, alcohol and fatty acid fractions). n-Alkanes and isoprenoid aliphatic alkanes, polycyclic alkanes of sterane and triterpane types, alcohols and fatty acids were analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). delta C-13(PDB) values of individual n-alkanes in the aliphatic fractions were determined using gas chromatography-isotope ratio monitoring-mass spectrometry (GC-irmMS). Results and discussion. Extracts 1 and 2 are characterized by uniform distribution of n-alkanes, whereas extract 3 is characterized by an even-numbered members dominating the odd-ones, and extract 4 showed a bimodal distribution. Extract I is characterized by the least negative delta C-13(PDB) values of C-19-C-26 n-alkanes. Sterane and triterpane analysis confirmed that all extracts originated from the same oil contaminant. n-Fatty acids, C-19-C-24, in all extracts are very low, being somewhat higher in extract 4. Even-numbered n-alcohols, C-12-C-16, were identified in the highest concentration in extract 3. It was assumed that algae were responsible for the composition of extract 3. Furthermore, a possible reason for higher concentrations of C-19-C-26 n-alkanes and C-19-C-24 fatty acids in extract 4 is the formation of inclusion compounds with colloidal micelles formed between the oil contaminant's NSO-compounds and water. Conclusion. It was undoubtedly confirmed that there were specific differences in the compositions of the different extracts depending on the intensity of the interaction between the oil contaminant and the surface water. Recommendation and Outlook. When comparing the composition of oil contaminants from different water samples (regardless of the ultimate investigation goal) it is necessary to compare the extracts isolated under the same conditions, in other words, extracts that were in the same or very similar interaction with water. Recommendation and Outlook. When comparing the composition of oil contaminants from different water samples (regardless of the ultimate investigation goal) it is necessary to compare the extracts isolated under the same conditions, in other words, extracts that were in the same or very similar interaction with water

A Comparative Investigation of an in vitro and Clinical Test of the Bifidogenic Effect of an Infant Formula

The bifidogenic effect of an infant formula supplemented with inulin and fructooligosaccharides (4.0 g/l) was examined clinically and in vitro, and compared that of mature breast milk. In a 28-day clinical study, fecal samples of 21 infants, divided into two groups: one receiving the infant formula and the other breast milk, were microbiologically and biochemically examined. In the in vitro investigation, microbiological and biochemical changes in the infant formula and breast milk induced by the action of bifidobacteria isolated from infant feces were examined. There were no significant differences in the fecal numbers of lactobacilli, total aerobes, anaerobes or yeasts and fungi. In contrast, the bifidobacteria numbers in the stools increased significantly during the study in the infants receiving the supplemented formula. The comparative in vitro test showed that the bifidogenic effect was similar for infant formula and breast milk in terms of the number of bifidobacteria. Consumption of infant formula with added inulin and fructooligosaccharides stimulated the bifidogenic effect, both clinically and in vitro. The in vitro test can quickly and objectively determine the bifidogenic effect of infant formula and indicate their quality. However, a clinical test is necessary to determine the acceptance and biological value of infant formula

A glucan from active dry bakers yeast (Saccharomyces cerevisiae): A chemical and enzymatic investigation of the structure

The structure of a polysaccharide consisting of D-glucose isolated from the cell-wall of active dry bakers yeast (Saccharomyces cerevisiae) was investigated by using methylation analysis, periodate oxidation, mass spectrometry, NMR spectroscopy, and enzymic hydrolysis, as a new approach in determination of structures. The main structural feature of the polysaccharide deduced on the basis of the obtained results is a linear chain of (1->3)-linked b-D-glucopyranoses, a part of which is substituted through the positions O-6. The side units or groups are either a single D-glucopyranose or (1->3)-b-oligoglucosides, linked to the main chaing through (1->6)-glucosidic linkages. The low optical rotation as well as the 13C-NMR and FTIR spectra suggest that the glycosidic linkages are in the b-D-configuration

Recombinant expression of monovalent and bivalent anti-TNT-antibodies – evaluation of different expression systems

Monoclonal 11B3 anti-TNT (trinitrotoluene) antibody was expressed as a monovalent and bivalent form using different prokaryotic and eukaryotic expression systems. Recombinant expression in Escherichia coli, mammalian cells and the methylotrophic yeast Pichia pastoris was performed to obtain disulfide-linked and glycosylated antibody forms. The generation of antibody and subsequent evaluation of the expression rates were performed using intracellular, excretory and periplasmatic expression techniques. All methods involved striving for native expressed antibody with maintenance of its functionality only

Comparative phytochemical analysis of Gentiana cruciata L. roots and aerial parts, and their biological activities

The purpose of this study was to evaluate the antioxidant potential of methanol extracts of Gentiana crudata L. aerial parts and roots, as well as the stability of the phenolic compounds and antioxidant capacity of extracts during heating, at different pHs and after an in vitro digestion procedure. Also, their genotoxicity and antigenotoxicity against carbon tetrachloride in the liver of albino Wistar rats using the comet assay were evaluated. Three secoiridoid glycosides (swertiamarin, gentiopicrin, and sweroside) and four phenolic compounds (orientin, vitexin and two isovitexin-glucosides) were identified as the major constituents in aerial parts and roots of G. cruciata, using UHPLC-DAD/+/- HESI-MS/MS analysis. The results of antioxidant assays showed that aerial parts displayed higher antioxidant activity compared to the roots, which could be related to higher phenolics content, especially flavonoids. In general, extracts showed pH and thermal stability, while duodenal condition had more influence on total phenolic condition and antioxidant activity of extracts. Both extracts showed a protective effect against CCl4 in comet assays. The roots extract showed no genotoxic activity, while aerial parts extract showed slight genotoxicity at concentrations of 400 mg/kg b.w. (C) 2015 Elsevier B.V. All rights reserved.Ministry of Education, Science and Technological Development of the Republic of Serbia {[}III 43004, III 41010, OI 173024

Comparative Analysis of Rhamnolipids from Novel Environmental Isolates of Pseudomonas aeruginosa

International audienceA comparative analysis of rhamnolipids from environmental isolates of Pseudomonas aeruginosa was undertaken to evaluate strain-specific rhamnolipid fingerprints obtained under different growth conditions. Environmental isolates of P. aeruginosa produced rhamnolipids on different types of substrates, including cheap and renewable sources like sunflower oil from deep fryers and sunflower oil mill effluent. Rhamnolipids were monitored by high-performance liquid chromatography–electrospray ionization interface mass spectrometry, which allowed fast and reliable identification and quantification of the congeners present. The highest concentration of total rhamnolipids of 3.33 g/l was obtained by the strain P. aeruginosa 67, recovered from petroleum contaminated soil, and strains D1 (1.73 g/l) and D2 (1.70 g/l), recovered from natural microbial consortia originated from mazut-contaminated soil, grown on sunflower oil as a carbon source. Di- to mono-rhamnolipids ratios were in the range of 0.90–5.39 for different media composition and from 1.12 to 4.17 for different producing strains. Rhamnolipid profiles of purified mixtures of all tested strains are similar with chain length from C8–C12, pronounced abundance of Rha–C10–C10 and Rha–Rha–C10–C10 congeners, and a low content of 3-(3-hydroxyalkanoyloxy)-alkanoic acids. Concentrations of major congeners of RLs were found to slightly vary, depending on strain and growth conditions, while variations in minor congeners were more pronounced. Statistically significant increase of critical micelle concentration values was observed with lowering the ratio of total mono- to di-rhamnolipids ratio indicating that mono-rhamnolipids start to form micelles at lower concentration than di-rhamnolipids