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Insufficient determination of the effect of surface-active substances introduced in extremely low concentrations on the formation of the stability of the properties of fine-grained concrete based on composite Portland cements determined the feasibility of conducting research in this area. The studies investigated the influence of the modification of composite cement with water activated by the use of the hydrophilic hydration mechanism. It has been proven that these factors include the type and amount of applied water nano modifiers. The analysis of the study results confirmed that the introduction of water activated by the mechanism of hydrophilic hydration into concrete in extremely small doses significantly increases the rate of formation of concrete strength and reduces the coefficient of its variation. Owing to this, the strength of the resulting modified fine-grained concrete based on composite cement at the age of 3 days exceeds the strength of the similar concrete without additives by 300 %, and at the age of 27 days – by 25 %. At the same time, the coefficient of variation of strength has a minimum value at the optimal amount of nano additive – water modifier. This allows us to assert the effectiveness of the revealed mechanism of modification of composite cement. Thus, there are reasons to assert the possibility of targeted regulation of the processes of formation of a strong homogeneous structure of fine-grained concrete based on composite cement by using water activated by the mechanism of hydrophilic hydration. [ABSTRACT FROM AUTHOR]

The use of the cholinesterase enzyme as a component of the analytical system has made it possible to develop a new kineticspectrophotometric method, which is alternative to the pharmacopoeial method, for determining the quaternary ammonium salt – ethonium in the substance and a dosage form. This method is characterized by high sensitivity and specificity, and is relatively cheap. The relative standard deviation of the procedure does not exceed 2.7 %, and the limit of quantification is 17 ng mL–1. [ABSTRACT FROM AUTHOR]

The object of research is fine-grained concrete on slag Portland cement. Owing to the significant content of metallurgical industry waste in its composition, slag Portland cement belongs to ecologically acceptable products. However, the insufficient rate of formation of its structure and, as a result, the main quality indicator, which is compressive strength, limits the field of use of slag Portland cement. Therefore, in the studies, the goal was to increase the speed of formation of the strength of fine-grained concrete made on slag Portland cement. The studies of the influence of modification of slag Portland cement with water, activated by the use of the hydrophobic hydration mechanism, established the factors affecting the speed of formation and the value of compressive strength of fine-grained concrete made on slag Portland cement. It has been proven that these factors include the type and amount of applied water nanomodifiers, as well as the type and amount of fine concrete aggregate. The analysis of the study results confirmed that the introduction of water activated by the mechanism of hydrophobic hydration into concrete in ultra-small doses significantly increases the rate of formation of concrete strength. Given this, the strength of the resulting modified fine-grained concrete based on slag Portland cement at the age of 2 days exceeds the strength of the similar concrete without additives by 60 %, and at the age of 210 days – by 25 %. This allows us to assert the effectiveness of the identified mechanism of modification of slag Portland cement. Thus, there are reasons to assert the possibility of targeted regulation of the processes of forming a strong structure of fine-grained concrete based on slag Portland cement by using water activated by the mechanism of hydrophobic hydration. [ABSTRACT FROM AUTHOR]

Copyright of Methods & Objects of Chemical Analysis / Metody & Obekty Himičeskogo Analiza is the property of Taras Shevchenko Kyiv National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The adhesive properties of brand BND 60/90 road bitumen with the oxidized phosphatide concentrate additive were studied. It was shown that the oxidized phosphatide increases the adhesive properties of bitumen brand BND 60/90. Oxidized phosphatide concentrate can be recommended as cost-effective alternative to expensive synthetic cationic surfactants, which are now widely used as adhesives for road bitumen. Based on the results of laboratory tests, the mathematical analysis of the obtained data was performed. Comparative graphs were plotted, and Pearson’s correlation coefficients and the approximation reliability values were calculated. It was found that the optimal composition for creating effective bituminous compositions with an increased thermo-physical and adhesive characteristics is 0.6 wt.% of oxidized phosphatide concentrate. [ABSTRACT FROM AUTHOR]

This work reports the structure of surfactants synthesized from by-products of the vegetable oil production. These are raw materials that do not compete with food products; they are lowcost phosphatidic sludge that can be used directly for chemical transformation. Fatty acid monoetanolamides derived from side streams of the vegetable oils production do not have residues of the original phosphatides or acylglycerols as determined by spectral methods. There are clearly reflected cross-peaks between the amide group and the adjacent methylene group. This indicates a high conversion of substrate and further confirms the amidation reaction. The main acyl residue of the synthesized surfactants are hydrocarbon chain of linoleic acid however, while the detection of methylene groups near double bonds indicates the presence of other fatty acids (oleic, linolenic and gadolein), this corresponds to the fatty acid composition of the original phosphatidic sludge. Synthesized surfactants are effective emulsifiers-stabilizers for dispersed systems. The use of environmentally friendly components in the composition of surfactants improves their biodegradability to 83-86%. [ABSTRACT FROM AUTHOR]

The increase in the number of resistant strains of Candida genus representatives, capable of forming biofilms on various surfaces, stimulates the search for new, alternative methods of combating them, one of which is the use of compounds of natural origin, such as essential oils. However, at the same time, their concentration should be minimal, which is due to the ability of essential oils to cause severe damage of the human's central nervous system and aspiration pneumonia. This leads to the necessity of searching for new methods to reduce the concentration of essential oils and at the same time to preserve their properties, in particular, by their use in a mixture with other antimicrobial agents, which can be microbial surfactants. Previously, it was found that the degree of yeast biofilm destruction under the action of Nocardia vaccinii IMV B-7405 surfactants dependson the nature of the growth substrate and is the highest in the presence of preparations synthesized on purified glycerol. Aim. To study the synergism of antifungal activity and the role in the destruction of biofilms of a mixture of Nocardia vaccinii IMV B-7405 surfactants synthesized on glycerol of different quality and essential oils. Methods. N. vaccinii IMV B-7405 was grown in a medium containing purified glycerol or waste from biodiesel production at a concentration of 2% (v/v) as carbon sources. The surfactants were extracted from the supernatant of cultural liquid by a modified Folch mixture. The antimicrobial activity of essential oils, surfactants, and their mixtures was determined by the index of the minimum inhibitory concentration. To assess the synergistic effect of a mixture of surfactants wiThessential oils, the fractional inhibitory concentration index was used. The degree of biofilm destruction (%) was determined as the difference between the cell adhesion in untreated and treated with surfactants, essential oil, or their mixture wells of the polystyrene microplates. Results. It was found that the surfactants synthesized by N. vaccinii IMV B-7405 on both purified glycerol and waste from biodiesel production showed synergistic antifungal activity in mixtures with cinnamon and lemongrass essential oils. Thus, the minimum inhibitory concentrations against Candida albicans D-6, Candida utilis BVS-65, and Candida tropicalis RE-2 of a mixture of surfactants synthesized on purified glycerol with cinnamon and lemongrass essential oils were 1.8--7.5 and 3.7--15 μg/mL, respectively, and were lower than in the case of using surfactants (30-60 μg/mL), cinnamon or lemongrass essential oil (156--312 μg/mL) alone. The use of a mixture of surfactants obtained on waste from biodiesel production and cinnamon or lemongrass essential oils made it possible to reduce the minimum inhibitory concentrations of the latter against studied yeast test cultures by 14--56 times. At the same time, the index of fractional inhibitory concentration did not exceed 0.5, which indicates the synergism of the antifungal activity of the mixture of these compounds. The destruction of Candida yeast biofilms under the action of surfactants synthesized on both purified glycerol and waste from biodiesel production in a mixture with cinnamon or lemongrass essential oils reached 60--67 and 67--77%, respectively, which is an average of 25--35% higher compared to the use of each monopreparation separately. Conclusions. The results presented in this paper confirm the previously obtained data that N. vaccinii IMV B-7405 surfactants, synthesized on both traditional substrates and toxic industrial wastes, have antimicrobial and antiadhesive synergistic action wiThessential oils, which allows us to consider them as potential components of the so-called «antifungal locks» in the fight against of Candida genus representatives. [ABSTRACT FROM AUTHOR]

The object of research is wastewater contaminated with anionic dyes. Traditional methods of wastewater treatment from dyes are imperfect and inefficient or non-existent. Therefore, the need to develop and implement effective and inexpensive to use and operate dye removal technologies is important. The biggest problem in dye removal is when large volumes of low concentration wastewater have to be treated. To purify just such effluents, a combined method, solvent sublation, has been proposed. It combines flotation and extraction methods and has the benefits of both. The essence of the method is the passage of gas bubbles through the aqueous phase and the transport of a hydrophobic complex (sublate) formed by a dye and a surfactant into the organic phase. The study used imitates of wastewater contaminated with an anionic dye, active bright blue in the concentration range of 5–50 mg/dm3. The influence of the main parameters on the degree of dye removal was studied: the pH of the initial solution, the molar ratio of surfactant: dye, the size of air bubbles, the gas flow rate, the initial concentration of the dye, the duration of solvent sublation. Rational parameters of the process have been established, which are advisable to use in solvent sublation: – purification process must be carried out in the presence of a cationic collector hexadecyltrimethylammonium bromide; – extractant – isoamyl alcohol; – molar ratio Dye: surfactant = 1:1.5; – pH 5.5; – generation of gas bubbles by a Schott filter with a porosity of 40 μm; – gas flow rate – 127 cm3/min. Under such conditions, the removal efficiency of active bright blue is 97 % at a process time of 10–25 min. The results obtained confirm the promise of the proposed method for the effective removal of dyes from lowconcentration aqueous solutions. The method has a number of advantages: it requires a small amount of extractant compared to liquid extraction; ions are concentrated in small volumes of an organic solvent; the process proceeds without phase mixing, so no emulsions are formed. [ABSTRACT FROM AUTHOR]

Introduction. The aim of this study was to investigate the role of surfactants synthesized by Acinetobacter calcoaceticus IMV B-7241 in media with glycerol in the presence of biological inductors in destruction of biofilms. Materials and methods. Cultivation of A. calcoaceticus IMV B-7241 was carried out in a mineral medium using refined glycerol or crude glycerol, the waste of biodiesel production, as carbon sources. Biological inductors were introduced as live or inactivated cells of Bacillus subtilis BT-2, as well as the supernatant after strain BT-2 cultivation. Surfactants were extracted from the supernatant of the culture liquid with a modified mixture of Folch (chloroform and methanol, 2:1). The degree of biofilm destruction in the presence of surfactants was determined by spectrophotometric method. Results and discussion. Regardless of the substrate used, the introduction of both live and inactivated cells of B. subtilis BT-2 into medium used for cultivation of A. calcoaceticus IMV B-7241 was accompanied by the synthesis of surfactants, the degree of biofilm destruction of which was higher than those obtained in the medium without an inductor. The degree of destruction of bacterial and yeast biofilms achieved by the action of A. calcoaceticus IMV B-7241 surfactants obtained on refined glycerol in the presence of inductor cells was 36.5-85% and was 1.5-3 times higher compared to using surfactants synthesized in medium without inductors. Note that, surfactants synthesized in the presence of biological inductors destroyed biofilms of the test cultures at fairly low (7.5-960 µg/ml) concentrations. Similar results were observed for the usage of surfactants obtained on the waste of biodiesel production. Therefore, introduction of live cells of B. subtilis BT-2 into the medium with the crude glycerol was accompanied by synthesis of surfactants, which at concentration 1.8-960 µg/ml caused destruction of B. subtilis BT-2, Proteus vulgaris PA-12 and Enterobacter cloacae C-8 biofilms at 30.1-80.7% and was higher than using similar surfactant concentrations obtained during cultivation without inductors (24.1-75%). The destruction of biofilms of Staphylococcus aureus BMS-1, Candida albicans D-6 and Candida tropicalis PE-2 under the action of surfactants (1.8-960 µg/ml) synthesized on crude glycerol in the presence of both live or inactivated cells of B. subtilis BT-2 was 1.5-8 times higher than surfactants synthesized in medium without inductor. Conclusion. The possibility to regulate the ability to destroy bacterial and yeast biofilms of surfactants synthesized by A. calcoaceticus IMV B-7241 by introducing into the medium competitive bacteria B. subtilis BT-2 was found. [ABSTRACT FROM AUTHOR]

The object of research is methods of increasing oil recovery in «old», depleted oilfields. One of the main tasks of the oil-extracting industry in any country in the world was and still is ensuring the project level of oil production at the maximum possible coefficient of its extraction from the subsoil. In this case it is extremely important to study and use technological methods and means of acquired experience in oilfield development. The paper considers the historical aspects of the development of stabilization and oil recovery methods from 1770s to the present day on the example of Ukrainian oilfields. In parallel with the history of the implementation of methods, their physical and technological content and conditions of application are discussed. Of all the methods used to increase the level of oil production, the most effective ones, which have found application at certain stages of the Ukrainian oilfields’ development, are considered. This is, first of all, a vacuum process, areal flooding, cyclic flooding, gas and water-gas repression, injection of surfactants, surfactant polymer-containing systems, polymer flooding, horizontal branched drilling. The methods development analysis is considered against the background of their geological and industrial acceptability and obtaining technical and economic effects. Based on the results of the study, a group of methods has been identified. These methods are advised to apply in geological and industrial conditions, similar to those described, which should ensure the expected efficiency. Undoubtedly, along with this, it is advisable to use the methods of mathematical modeling of oilfield development processes. Proposals are formulated on the conditions and principles of applying the methods under consideration in order to improve the systems for the development of oilfields. It has been established that the most acceptable methods of increasing oil recovery in depleted oilfields are the injection of surfactant solutions both independently and together with an aqueous solution of polyacrylamide, creation of gas-water repression and polymer flooding, in which preference is given to AN132SH and AN125SH reagents of FLOPAAM S series from SNF FlOERGEL. [ABSTRACT FROM AUTHOR]

Introduction. The aim of this research was to study the biological activity of surfactants synthesized by Acinetobacter calcoaceticus IMV B-7241 in the medium with glycerol of various degrees of purification and high content of calcium cations (activators of NADH+-dependent glutamate dehydrogenase, which is a key enzyme of biosynthesis of surface-active aminolipids responsible for antimicrobial activity of surfactant complex). Materials and methods. Cultivation of A. calcoaceticus was carried out in liquid mineral medium using as substrates refined glycerol and the waste from biodiesel production. The base medium did not contain calcium chloride, the content of CaCl2 in the modified medium was 0.1 and 0.2 g/l. Surfactants were extracted from the supernatant of the culture luquid with a modified mixture of Folch. The number of adhered cells and the degree of biofilm destruction in the presence of surfactants was determined by spectrophotometric method, antimicrobial activity of surfactants - by the minimum inhibitory concentration (MIC). Results and discussion. It was found that the additional introduction of 0.1-0.2 g/l of CaCl2 into cultivation medium with refined glycerol was accompanied by the synthesis of surfactants, the MIC of which against bacteria (Bacillus subtilis BТ-2, Enterobacter cloacae C-8, Staphylococcus aureus BМS-1) and yeast (Candida albicans D-6) were 1.01-21.3 μg/ml and were 1.4-29 times lower compared to the MIC of surfactants obtained in base medium (1.83-58.8 μg/ml). The adhesion of test cultures on abiotic materials treated with such surfactants was 8-13% lower, and the degree of biofilms destruction was 5-19% higher compared to the values, established for surfactants obtained on base medium. The increasіng antimicrobial and anti-adhesive activity of surfactants synthesized on waste of biodiesel production was observed only when CaCl2 was introduced into the medium at a concentration of 0.2 g/l. Surfactants synthesized in the presence of calcium cations in the medium with the waste of biodiesel production proved to be more effective destructors of bacterial biofilms in comparison with those obtained in the base medium only at low concentrations (0.7-5.5 μg/ml). Conclusion. The results demonstrate the possibility of regulating the biological activity of A. calcoaceticus IMV B-7241 surfactants by changing in the composition of medium content of calcium cations - activators of NADH+-dependent glutamate dehydrogenase (key enzyme of surface-active aminolipids biosynthesis). Surfactants synthesized under different cultivation conditions of A. calcoaceticus IMB B-7241 on glycerol are more effective biofilm destructors and antimicrobial and anti-adhesive agents compared to the known lipopeptides and rhamnolipids formed on glycerol. [ABSTRACT FROM AUTHOR]

The formation of pathogenic microorganisms biofilms on the central venous catheter is the cause of catheter-associated infections. An alternative method of combating biofilms is the use of "antibacterial" and "antifungal" locks, which are solutions of antibiotics or antifungal drugs in a mixture with other natural compounds, which can be microbial surface-active substances (surfactants) or essential oils. Aim. To investigate the role of Nocardia vaccinii IMV B-7405 surfactants mixture with other antimicrobial compounds in the destruction of biofilm on silicone tubes. Methods. N. vaccinii IMV B-7405 was grown in medium containing as carbon source purified glycerol and waste from biodiesel production, refined sunflower oil, oil after frying French-fried potatoes, Potato wedges and meat. The surfactants were extracted from supernatant of cultural liquid by modified Folch mixture. 2 mL of surfactant solutions, antifungal drugs (nystatin, fluconazole) or tea tree essential oil of the same concentration (5-640 μg/mL) were added to test tubes with silicone tubes (with pre-formed biofilm from test culture). To study the synergistic effect of the biofilms destruction, a mixture of surfactant solutions and antifungal substances (or essential oil) of the same concentration in a ratio of 1:1 (1 mL of each solution) was added to the test tubes. Sterile tap water (2 mL) was added to control test tubes instead of surfactants preparations, antifungal substances or essential oil. The degree of biofilm destruction (%) was determined as the difference between the adhesion of cells on the inner side of silicone tubes, untreated and treated with surfactants, antifungal drugs, essential oil, or their mixture. Results. It was found that surfactants synthesized by N. vaccinii IMV B-7405 on all substrates showed synergism of yeast and bacterial biofilms destruction on silicone tubes in a mixture with nystatin, fluconazole and tea essential oil in the whole range of investigated concentrations (5-640 μg/mL), but the highest effect was achieved at a concentration of 20-40 μg/mL. Thus, the degree of Candida albicans D-6, Candida utilis BVS-65 and Candida tropicalis PE-2 biofilms destruction under the action of a mixture of surfactants synthesized on waste from the biodiesel production and waste oil, with antifungal drugs was 45.8-71.8 % and was higher than with only surfactants (21.2-41.6 %), nystatin (22.4-24.1 %) or fluconazole (28.1-31.3 %). The destruction of Candida genus yeast biofilms under the action of surfactants synthesized on oil-containing substrates in a mixture with both nystatin and fluconazole reached 50.1-71.2 %, which is 10-30 % higher compared to the use of surfactants alone or only antifungal agents. The degree of Pseudomonas sp. MI-2, Escherichia coli IEM-1, Staphylococcus aureus BMS-1, Bacillus subtilis BT-2 (spores) biofilms destruction on silicone tubes treated with a mixture of tea tree essential oil and surfactants synthesized on all oil-containing substrates was 10-29 % higher than in the case of using only solutions of surfactants (11.5-45.4 %) or essential oil (21.4-34.5 %) for the tubes treatment. Conclusions. The data obtained make it possible to consider surfactants synthesized by N. vaccinii IMV B-7405 on a wide range of cheap and accessible substrates as promising components of "antibacterial" and "antifungal" locks in combination with essential oils and antifungal agents. [ABSTRACT FROM AUTHOR]

Наведено результати досліджень впливу різних класів розчинників на олієвмісні забруднення на поверхні деталей із вуглецевої сталі перед нанесенням йонно-плазмових покриттів. Як розчинники використано С6Н14, С8Н18, С6Н6, СНСl3, CCl4, С2Н4Сl2, С2Н5ОН, С4Н9ОН, С2Н5ОСОСН3, NaOH, HCl. Забруднювачами поверхні були солідол і мастильно-охолоджувальна рідина (МОР) Укрінол-4. Для зразків, оброблених солідолом, найкращий результат зафіксовано в неполярного розчинника октану С8Н18 і слабкополярного розчинника етилетаноату С2Н5ОСОСН3, для яких втрата маси перевищила 1 %. Втрату маси більше ніж 0,5 % виявлено в неполярних розчинників і хлорозаміщених вуглеводнів. У неполярних розчинників ступінь очищення покращувався зі зростанням молярної маси розчинника та насичення Гідрогеном, а для хлорозаміщених вуглеводнів – із зростанням вмісту Хлору. Найкращі результати очищення зі спиртів виявлено в ізобутанолу С4Н9ОН. Зразки, оброблені МОР Укрінол-4, відмивали розчинниками CCl4, С2Н5ОН, С6Н14, С2Н4Сl2, що свідчить про вагомий внесок поверхнево-активних речовин (ПАР) і присадок, що присутні у складі МОР. Здатність до очищення зростає у такій послідовності: лужні та кислі водні розчини спирти хлорозаміщені вуглеводні неполярні та слабкополярні розчинники. Досліджено фізико-хімічні властивості та визначено вміст сторонніх продуктів в оливах класу HLP для гідросистем і для напрямних верстатів. Проведено порівняння ІЧ-спектрів свіжої та вживаної олив. Встановлено, що в процесі роботи олива окиснюється. Найбільше процес експлуатації вплинув на зростання кислотного числа (в три рази) та вмісту води (в дев'ять разів).

Magnesium oxide (MgO) nanoparticles have been widely used in a variety of applications because of their good surface reactivity. Magnesium oxide from bittern has a larger surface area compared to magnesium oxide from calcined magnesite and magnesium ions precipitation from bittern using sodium hydroxide has higher purity than using calcium hydroxide or ammonium hydroxide. In this research, sodium hydroxide was added to a bittern solution obtaining magnesium hydroxide precipitate, followed by the calcination process to produce magnesium oxide. Nano magnesium oxide was synthesized by the ultrasonic destruction process using ethanol and 2-propanol as media. In this study, sonication time and particle concentration effect on the ultrasonic destruction process were investigated. During the process, the sonication time was varied between 8, 16, 32, 64, and 128 minutes while the magnesium oxide concentration was varied between 1 %, 2 %, and 3 %. Increasing sonication time and particle concentration will decrease the particle size. The previous study shows that particles with very small sizes tend to have an agglomeration effect. The aim of this work is to optimize nano magnesium oxide production from bittern. Surfactant addition was also studied to prevent agglomeration between particles. Four types of surfactant namely anionic (sodium lauryl sulfate), cationic (cetyl tri-methyl-ammonium bromide), amphoteric (fatty acid amido alkyl betaine), and non-ionic (nonylphenol 10 ethoxylated) with a concentration of 1 % and a volume of 0.125 ml were added during the second ultrasonic destruction process. All types of surfactants have a positive effect to prevent agglomeration during the ultrasonic destruction process, with the amphoteric surfactant having the highest performance [ABSTRACT FROM AUTHOR]

Until recently, there were rare scientific reports on the biotechnological potential of non-pathogenic bacteria of the Acinetobacter genus. Although the first reports about the practically valuable properties of these bacteria date back to the 70s and 80s of the twentieth century and concerned the synthesis of the emulsan bioemulsifier. In the last decade, interest in representatives of the Acinetobacter genus as objects of biotechnology has significantly increased. The review presents current literature data on the synthesis by bacteria of this genus of high-molecular emulsifiers, low-molecular biosurfactants of glyco- and aminolipid nature, enzymes (lipase, agarase, chondroitinase), phytohormones, as well as their ability to solubilize phosphates and decompose various xenobiotics (aliphatic and aromatic hydrocarbons, pesticides, insecticides). Prospects for practical application of Acinetobacter bacteria and the metabolites synthesized by them in environmental technologies, agriculture, various industries and medicine are discussed. The data of own experimental studies on the synthesis and biological activity (antimicrobial, anti-adhesive, ability to destroy biofilms) of biosurfactants synthesized by A. calcoaceticus IMV B-7241 strain and their role in the degradation of oil pollutants, including complex ones with heavy metals, are presented. The ability of A. calcoaceticus IMV B-7241 to the simultaneous synthesis of phytohormones (auxins, cytokinins, gibberellins) and biosurfactants with antimicrobial activity against phytopathogenic bacteria allows us to consider this strain as promising for practical use in crop production to increase crop yields. [ABSTRACT FROM AUTHOR]

Microbial surfactants (biosurfactants) are multifunctional preparations due to a combination of physicochemical (reduction of surface and interfacial tension, emulsifying activity) and biological (antimicrobial and antiadhesive activity, the ability to destroy biofilms) properties. However, the disadvantage of biosurfactants synthesized as a complex of compounds is the possibility of changing the biological activity depending on the conditions of producer cultivation. Aim. To study the effect of potassium and sodium cations on the NADP+-dependent glutamate dehydrogenase activity of cell-free extract of Acinetobacter calcoaceticus ІМV B-7241 with subsequent appropriate modification of the nutrient medium composition and determination of antimicrobial and anti-adhesive activity of surfactant synthesized. Methods. A. calcoaceticus ІМV B-7241 strain was grown in media containing 2% of sunflower oil waste as a carbon source, as well as various concentrations of potassium and sodium chloride (basal - 1.0 g/l NaCl, medium #1 that did not contains NaCl, medium #2 in which the concentration of NaCl was 2.0 g/l, medium #3 in which the concentration of NaCl and KCl was 1.0 g/l each). The surfactants were extracted from the supernatant liquid culture with a modified Folch mixture. Anti-adhesive activity and the degree of biofilms degradation were determined by spectrophotometric method, antimicrobial activity - by the indicator of the minimum inhibitory concentration (MIC). Activity of enzymes of surface-active aminolipids biosynthesis (NADP+-dependent glutamate dehydrogenase) and glycolipids (phosphoenolpyruvate (PEP) carboxylase, PEP-synthetase, PEP-carboxykinase, trehalose phosphate synthase) were analyzed in cell-free extracts obtained after the destruction of cells by ultrasound. Results. It was found that potassium and sodium cations in concentrations of 50 and 100 mM are inhibitors of NADP+-dependent glutamate dehydrogenase, and in lower concentrations (5-20 mM) - activators of this enzyme, as well as PEP-carboxykinase and PEP-synthetase. The increase in the biosurfactant concentration to 6.1-7.7 g/l during cultivation of A. calcoaceticus ІМV B-7241 in medium #1 and #3 was due to the predominant synthesis of glycolipids under such conditions, which was evidenced by the increase in 1.8-6.5 times in the activity of PEP-carboxylase, PEP-carboxykinase, PEP-synthetase and trehalose phosphate synthetase compared to the indicators on the basal medium. The concentration of surfactants synthesized in the basal medium was 3.6 g/l, but such surfactants were characterized by the highest antimicrobial and anti-adhesive activity. Their MIC against the test-cultures of studied bacteria (Pseudomonas sp. MI-2, Bacillus subtilis BT-2, Escherichia coli IEM-1, Staphylococcus aureus BMS-1, Enterobacter cloaceae C-8) and fungi (Candida albicans D-6, Rhizopus nigricans P1, Aspergillus niger P-3, Fusarium culmorum T-7) were 0.88-56 μg/ml and were by 2-3 orders of magnitude lower compared to established for surfactants synthesized in modified media #1-3. In the case of treatment of abiotic materials with surfactant solutions obtained on the basal medium, the adhesion of bacteria and fungi was on average 10-20 % lower than after surface treatment by the surfactant synthesized in modified media. In the presence of 148-296 μg/ml of surfactants obtained in the basal medium, destruction of S. aureus BMS-1 and B. subtilis BT-2 biofilms was 45-66 %, and C. albicans D-6 yeast - 39-44 %. Under the action of similar concentrations of surfactants synthesized in modified media, the destruction of bacterial and yeast biofilms was lower: 6-52 and 20-46 %, respectively. Conclusions. The obtained results are consistent with the data of our previous studies on the possibility of regulating the antimicrobial and antiadhesive activity of surfactants in the process of producer cultivation by changing the content of cations in the medium, which are inhibitors/activators of enzymes responsible for the synthesis of components of the surfactants complex, which have certain biological properties. [ABSTRACT FROM AUTHOR]

Copyright of Scientific Bulletin of National Mining University is the property of National Mining University, State Higher Educational Institution and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Currently, microbial surfactants are the objects of intense research because of their surface-active and emulsifying properties, high antimicrobial, anti-adhesive activity, and ability to destroy biofilms. The review provides current literature data on the properties of surfactants synthesized by Rhodococcus genus actinobacteria, determining their practical significance. The researchers' interest in the surfactants of Rhodococcus bacteria is primarily due to their key role in the destruction of xenobiotics (aliphatic, heterocyclic and polycyclic aromatic hydrocarbons). Information on the antimicrobial and antiadhesive activity of surfactants of Rhodococcus genus bacteria remains scarce at present, while the immunomodulatory properties of these products of microbial synthesis are studied more actively than for other microbial surfactants known in the world. The data of our experimental studies on the practically valuable properties of surfactants synthesized by Rhodococcus erythropolis IMV Ac-5017 are presented. Unlike surfactants of other representatives of Rhodococcus genus bacteria, surfactants of IMV As-5017 strain are multifunctional preparations. Because in addition to the high efficiency of the destruction of oil pollution, including complex with heavy metals, surfactants are characterized by high antimicrobial and antiadhesive activity, including the ability to destroy biofilms. [ABSTRACT FROM AUTHOR]

An increase in the antibiotic resistance of pathogenic microorganisms has stimulated the search for alternatives to antibiotics substances of natural origin, which are essential oils (EO) and non-toxic biodegradable microbial surfactants. Aim. To investigate the antimicrobial and anti-adhesive activity of a mixture of EO and surfactants of Nocardia vaccinii IMV B-7405 synthesized on various oil-containing media. Methods. N. vaccinii IMV B-7405 was grown in medium containing as carbon source refined sunflower oil, oil after frying french fried potatoes, potato wedges and meat. The surfactants were extracted from supernatant of cultural liquid by modified Folch mixture. The antimicrobial action of tea tree, cinnamon and lemongrass EO, surfactants and their mixtures was determined by index of the minimum inhibitory concentration (MIC). Synergistic effect of surfactants and EO was evaluated by indicator of fractional inhibitory concentration. The degree of bacteria and fungi biofilms destruction under the action of surfactants, EO and their mixtures was determined by spectrophotometric method. Results. It was found that N. vaccinii IMV B-7405 surfactants synthesized on all oil-containing substrates showed a synergistic antimicrobial and anti-adhesive activity with the investigated EO. MIC of a surfactants and EO mixture against bacteria (Bacillus subtilis BT-2 (spores), Escherichia coli IEM-1, Staphylococcus aureus BMS-1) and yeast (Candida albicans D-6, Candida utilis BVS-65 and Candida tropicalis RE-2) were 2-20 μg/ml and were significantly lower than each compound separately (156-625 and 8-80 μg/ml for EO and surfactants, respectively). The destruction of bacterial and yeast biofilms under the action of a mixture of surfactants (20-40 μg/ml) and EO (20-40 μg/ml) was 1.3-2.9 times higher compared with using of each component separately at similar concentrations. Conclusions. The data presented the possibility of using a mixture of EO and surfactants not only to reduce their MIC, but also as effective antimicrobial and anti-adhesive agents. [ABSTRACT FROM AUTHOR]

The results are presented of a study on spectral characteristics, electron microscopy data and antibacterial properties of Lactobacillus plantarum cell matrices filled with biologically synthesized in the presence of surfactants (S) silver nanoparticles (bioAgNP). The dependences of spectral characteristic of cell suspension of lactic acid bacteria L.plantarum with synthesized bioAgNP on S concentration were analyzed, namely: cationic two quaternary ammonium salt (CS) aethonium and anionic sodium decyl phosphate (AS). To control the process of bioAgNP production in microorganism cells, the method of spectroscopy in ultraviolet and visible regions was used. The antibacterial properties of modified L. plantarum cells dependent on synthesis condition and their composition were testified by disco diffusion method. The results are presented of electron-microscopy investigation of treated with concentrated sulfuric acid bionanocomposite material. It is shown that addition at the synthesis of an ionogenic S to the precursor solution affects structural and size descriptions of biogenic silver formed in L. plantarum cells. Since a concentration more then the critical concentration of micelle formation, aethonium presence resulted in forming of two NPs fractions, namely: stabilized in a cell wall subcolloidal particles having absorption band at 380 nm and also aggregated particles having spectral shoulder at 440 nm. S addition promoted the red shift of absorption spectra dependent on CS concentration and medium pH, however not dependent on AS concentration. It is shown that antibacterial properties of modified with S nanobiocomposite materials mainly depend on the NPs content in lactic acid matrices and on their size. Joint application of bionanocomposite and aethonium preparation close to the critical micelle concentration allowed to rise their activity in relation to Gram(+)bacteria and, at the same time, to bring down on an order (from 1.0 to 0.1 %) the ordinary therapeutic dose of aethonium. [ABSTRACT FROM AUTHOR]

This review analyses the authors’ recent and related works on electrokinetic properties and colloidal stability of aqueous suspension of multi-walled carbon nanotubes (CNTs) in the presence of surfactants and nanoparticles. Selected adsorptive properties of carbon nanotubes are also considered. The applicability of classical theories of electrophoresis for description of electrophoretic mobility of carbon nanotubes is discussed. Examples on the ζ-potential of CNTs in aqueous suspensions as a function of pH and concentration of electrolytes (KCl, CaCl2 and AlCl3) are given. Additions of cetyltrimethylammonium bromide (CTAB) cationic surfactant below the critical micelle formation concentration (CMC) values give a reduction and then an overcharging the CNT surface because of accumulation of the surfactant ions in the Stern layer. At concentrations above CMC the substantial drop in ζ-potential is observed. It is due to the shift of the shear plane toward solution as a result of formation of hemi-micelles on the surface. An increase in the mass ratio of artificial mineral Laponite (Lap) in suspension (X) from 0 to 0.4 results in a monotonic decrease of the ζ-potential of CNT + Lap hybrids with reaching its plateau value ≈ –32 mV at X ≥ 0.4 that corresponds to the ζ-potential of “pure” Lap platelets. This evidences the high surface coverage of nanotubes surface with Lap at X ≥ 0.4. The major methods to improve the dispersibility of carbon nanotubes, their colloidal stability and adsorptive properties are briefly discussed, namely: stabilization in mixtures of water and organic solvents; functionalization by chemical treatment; stabilization by additives of surfactants or polymers and hybridization by addition of supplementary stabilizing nanoparticles. CNTs can be significantly debundled in “good” solvents, such as 1- cyclohexyl-2-pyrrolidone, N,N-dimethylformamide, or N-methyl-2-pyrrolidone. It is demonstrated that the dispersibility of CNTs is a complex function of the type of surfactant, its concentration and the surfactant/CNTs ratio. The optimum concentration of CTAB to achieve homogeneous aqueous dispersion of carbon nanotubes was identified to be near the CMC. Additions of CTAB significantly modify the size distribution of CNTs and a sharp transition from small primary aggregates to large secondary aggregates at concentrations above CMC is observed. At optimal concentration of Lap the nanotube particles get well stabilized, and a stepwise increase of sedimentation stability is observed. We have shown also that CNT + Lap hybrids can be effectively used for removal of methylene blue dye from aqueous systems. The kinetics and mechanisms of adsorption are elucidated. [ABSTRACT FROM AUTHOR]

Мета. Дослідити антагоністичну, нафто- і ПАР-деструктивну активність бактерій, ізольованих із прибережних зон Чорного моря. Методи. Для ізоляції бактерій – деструкторiв з морської та порової води зони заплеску Одеської затоки, о. Зміїний використовували метод накопичувальних культур на рідкому синтетичному середовище МКД з подальшим висівом на живильні середовища МПБ та М-9, що містили окремо нафту і додецилсульфат натрію у концентрації 1%. Дослідження антагоністичної активності, що оцінювали за величиною зон затримки росту тест-штамів, проводили за методом відстрочених посівів. Результати. Вивчено деструктивну і антагоністичну активність 58 штамів бактерій, ізольованих із прибережних зон Чорного моря. Деструктивну активність що до нафти і ПАР виявили 36 досліджуваних штамів. З найактивніших відібрано 3 штами-деструктори, які проявили найбільшу інгібуючу дію щодо тест-штамів умовно патогенних мікроорганізмів, у тому числі санітарно-показових. Найбільшу кількість штамів-антагоністів ізольовано з порової та морської води у районі скиду міських господарсько-фекальних вод на Дачі Ковалевського, що свідчить про хронічне хімічне та біологічне забруднення зони заплеску в цьому районі одеського узбережжя Чорного моря. Висновок. Поліфункціональні штами M. barkeri 5, M. barkeri 13, P. fluorescens 55, які виявили високий рівень антагоністичної активності щодо широкого спектра представників умовно-патогенної мікробіоти і мали високу здатність окислювати вуглеводні нафти і ПАР, можуть бути рекомендовані для подальшого використання в біотехнологіях ремедіації морських вод від біологічного і хімічного забруднення.

The adsorption of cationic hexadecylpyridinium bromide and non-ionic oxyethylated octylphenols (TХ-45, TX-100, ТХ-305) surfactants from their mixed solutions at non-porous hydrophobic carbon sorbent such as thermal graphitized carbon black has been studied. The molar fraction of oxyethylated octylphenols in the mixtures was 0.2, 0.4, 0.6, and 0.8. The results have shown that the adsorption values of hexadecylpyridinium bromide depend on the total concentration of the surfactant and the composition of mixtures. It has been found that the molar fraction of nonionic surfactants in the mixed adsorption layers at carbon black surface decreases in the series: ТХ-45 > ТХ-100 > ТХ-305. The regularities of the change in the surface activity of the surfactant mixtures at the solution-solid sorbent interface with an increase in the total surfactant concentration in the solution correlate with those for the solution-air system, but are more pronounced. The areas per hexadecylpyridinium bromide and the oxyethylated octylphenols molecules in the adsorption layer while adsorbing from their binary solutions are lesser than ones for the surfactants adsorption from their individual solutions, and smaller than the corresponding areas at the solution-air interface. These findings indicate the consolidation of the adsorption layer at the solid surface and confirm that the surfactants adsorb at carbon black surface as associates. [ABSTRACT FROM AUTHOR]

The formation of biofilms on various surfaces is a dangerous phenomenon, since microorganisms in their composition are characterized by increased resistance to different biocides. Therefore, the search for new effective compounds capable of destroying biofilms, including microbial surfactants, is actual. Aim. To study the effect of the cultivation conditions of Nocardia vaccinii IMV B-7405 on the ability of the synthesized surfactants to destroy biofilms. Methods. The IMV B-7405 strain was grown in a medium with purified glycerol, refined and fried sunflower oil of various qualities, waste of biodiesel production and a mixture of substrates until the early and late stationary growth phase. The surfactants were extracted from supernatant of cultural liquid with a mixture of chloroform and methanol (2:1). The degree of biofilm destruction was determined by spectrophotometric method. Results. It was established that the degree of bacterial and yeast biofilms destruction in the presence of surfactants depended on the cultivation conditions of N. vaccinii IMV B-7405 (nature, concentration, quality of the growth substrate and the duration of the process). The highest degree of bacterial biofilms destruction (53–78%) was observed under the action of surfactants synthesized on a mixture of waste of biodiesel production and molasses. The destruction of Candida albicans D-6 biofilm was maximal (52–72%) in the presence of surfactants obtained on purified glycerol. Increasing the duration of N. vaccinii IMV B-7405 cultivation on refined and after frying «potato selyanski» oil was accompanied by the synthesis of surfactants, under the action of which the degree of destruction of bacterial test cultures biofilms decreased 1.3−2.2 times. Higher destruction of biofilms in the presence of supernatants compared to using surfactants solutions of similar concentration may be due to the synthesis of N. vaccinii IMV B-7405 other, non-surfactant, metabolites capable of destroying biofilms. Conclusions. The presented data indicate that surfactants synthesized under different cultivation conditions of N. vaccinii IMV B-7405 are capable to destroy bacterial and yeast biofilms. The dependence of the biofilms degree destruction in the presence of surfactants on the producer growing conditions must be considered when technologies of production of these microbial synthesis products are being developed. [ABSTRACT FROM AUTHOR]

The results of the study of lubricating layers formed by oils with surface-active additives on the quality of running-in of friction pairs with local contact under rolling with sliding are presented. Тhe effect of formic acid (surface-active substances - SAS) on the process of running- in in the mineral oil MK-8 medium, which intensively forms SOP already at room temperature, was investigated. The experiments were carried out on a friction machine SMC-1 on roller specimens made of normalized steel 45 with a hardness of HB 220, with a roughness of Rz of working surfaces of 4-3,2 microns, at constant contact stresses of 700MPa, a total rolling speed of VΣ 4,23m/s and a slip factor of 20%. Formic acid additive was introduced into MK-8 oil immediately before the experiments. The main parameters characterizing the running-in process were the thickness of the lubricating layer h, the friction coefficient fter. and the final roughness Rz. The method of kinematic friction pairs running-in in the lubricating medium is proposed, which is based on the principle of regulating the thickness and condition of the third body, which is effective for surface treatment when the main purpose is to minimize wear during the working period. It is shown that the introduction of SAS into oils suppresses the formation of self-generating organic films (SOPs), which leads to accelerated running-in of contact surfaces. The subsequent heating of the oil to the desorption or decomposition of SAS molecules after receiving the contact spot stimulates the formation of SOPs and contributes to the rapid transition to the load range corresponding to the minimum value of wear of the contact surfaces. [ABSTRACT FROM AUTHOR]

Aim. To determine the conditions of Nocardia vaccinii IMV B-7405 cultivation on mixture of crude glycerol (waste of biodiesel production) and frying sunflower oil, which provide the maximum parameters of surfactants synthesis. Methods. The surfactants concentration was determined by gravimetrically after extraction from the supernatant of the culture liquid with a modified mixture of Folch (chloroform-methanol-water =4:3:2, pH 4.0-4.5 with addition of 1N HCl). The optimal molar ratio of refined sunflower oil and purified glycerol concentrations in mixture was calculated theoretically according to the concept of «auxiliary substrate» of Babel. Results. Based on theoretical calculations of the energy requirements for N. vaccinii IMV B-7405 biomass production and the synthesis of surface-active trehalose mycolates on the energy-deficient substrate (glycerol), it was established that the molar ratio of refined sunflower oil and purified glycerol concentrations in mixture providing maximum surfactant synthesis should be 0.16:1. Experimental studies have shown that highest values of surfactant synthesis were observed when the molar ratios of these substrates concentrations was 0.14:1-0.19:1, which is as close as possible to the theoretically calculated one. The possibility of replacing purified glycerol and refined sunflower oil in mixture with biodiesel production waste and frying oil was established. At a molar ratio of frying oil and crude glycerol concentrations in mixture 0.078:1 (considering 50% of glycerol content in biodiesel production waste) and using inoculum grown on crude glycerol, the amount of synthesized surfactants was 5.1-5.4 g/l, which is 1.6-2.3 times higher in comparison with the cultivation of N. vaccinii IMV B-7405 on corresponding monosubstrates. Conclusions. The obtained results confirm the previous data on the advisability of using mixture of energetically unequal growth substrates to increase the synthesis of secondary metabolites and show that high efficiency of such mixed substrates can be achieved both with the correct choice of substrates and the correct determination of their concentrations molar ratio. The using frying sunflower oil and crude glycerol for production of microbial surfactants will solve several important problems simultaneously: reduce the cost of final product, utilize toxic industrial waste, and increase rentability of biodiesel production. [ABSTRACT FROM AUTHOR]

Copyright of Biological Resources & Nature Management is the property of National University of Life & Environmental Sciences of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Naukovi visti NTUU - KPI is the property of National Technical University of Ukraine KPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Eastern-European Journal of Enterprise Technologies is the property of PC TECHNOLOGY CENTER and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. Investigation of the wetting ability of surfactants solutions of various classes in relation to a grey cotton knitted fabric. Methodology. The wetting ability of surfactants solutions of different concentrations was determined by the Draves immersion method. Findings. The paper presents the results of the study of the wetting ability of surfactants solutions of various classes in relation to grey cotton knitted fabric. Originality. For the first time, the dependence of the wetting time of the samples of grey cotton knitted fabric on the concentration of surfactants of various classes was established. Practical value. Surfactants and their concentrations are established, which ensure the maximum rapid wetting of knitwear. [ABSTRACT FROM AUTHOR]

Aim. Comparison of biological properties (antimicrobial and anti-adhesive activity, including role in biofilms destruction) of surfactants Acinetobacter calcoaceticus IMV B-7241, synthesized on purified and technical glycerol (waste of biodiesel production). Methods. The surfactants were extracted from supernatant of cultural liquid with a mixture of chloroform and methanol (2:1). The number of adherent cells and the degree of biofilm destruction were determined by the spectrophotometric method, the antimicrobial properties of the surfactants were analyzed by the minimum inhibitory concentration. Results. The antimicrobial activity of A. calcoaceticus IMV B-7241 surfactants synthesized on technical glycerol was 1−2 orders lower, adhesion of test cultures on abiotic materials treated with such preparations was 1.2−4 times lower and degree of bacterial biofilms destruction − in 1,3−4 times less in comparison with the parameters established for surfactants, obtained on medium with equimolar by carbon concentration of purified glycerol.The decreasing antimicrobial and anti-adhesive activity of the surfactants may be due to the inhibitory effect of K+ and Na+ excess concentration (components of technical glycerol) on the activity of NADP+-dependent glutamate dehydrogenase: in the presence of 50‒100 mM of potassium and sodium cations enzymatic activity decreased in 1,2−1,8 times. Conclusions. Despite the lower antimicrobial and anti-adhesive activity of surfactants synthesized by A. calcoaceticus IMV B-7241 on waste of biodiesel production, these values (minimum inhibitory concentrations 0.96−15.2 μg/ml, degree of biofilms destruction by 50% at surfactants concentration of 124 μg/ml) are comparable with those established for known microbial surface-active aminolipids. [ABSTRACT FROM AUTHOR]

Purpose. Comparison of dimensional characteristics of various non-wood fibers (flax, hemp, bamboo, cotton), which can be used as an additional component in the production of non-woven composite materials from synthetic fibrous waste. Method. The structure of the fibers was studied by optical polarization microscopy. The dimensional characteristics of the fibers were determined by the method of analyzing digital images, followed by statistical processing and graphical analysis of the obtained data. Results. A quantitative comparative analysis of the transverse dimensions and distribution for this indicator for non-wood fibers of various natural origin: flax, hemp, bamboo, cotton. It has been established that the average transverse dimensions of the initial fibers of flax and hemp are higher than for bamboo and cotton fibers with greater variability of this index and a pronounced asymmetry of the distribution towards valuesgreater than the average. Scientific novation. Based on a detailed statistical analysis of microscopic images, differences in the transverse dimensions of non-wood fibers of different natural origin are established. Practical value. The results obtained can be used to produce nonwoven composite materials with predictable properties. [ABSTRACT FROM AUTHOR]

Мета. Аналіз механізму дії поверхнево-активних речовин в умовах промивання бавовняного трикотажу, встановлення поверхнево-активних речовин за функціональним призначенням, які мають входити до складу композиції та дослідження зміни поверхневого натягу розчинів поверхнево-активних речовин різних класів, призначених для створення композицій для підготовки бавовняного трикотажного полотна. Методика. Визначення поверхневого натягу розчинів поверхнево-активних речовин різної концентрації проводилось методом відриву кільця - методом Дю-Нуї. Результат. У роботі наведені результати аналізу механізму дії поверхнево-активних речовин в умовах промивання бавовняного трикотажу, встановлено, які властивості повинні мати складові композиції та визначено поверхнево-активні речовини, що сприяють максимальному зниженню поверхневого натягу їх розчинів. Наукова новизна. Науково обґрунтовано принципи створення композицій поверхнево- активних речовин для промивання бавовняного трикотажного полотна на основі аналізу механізму їх дії та встановлено, що визначальними є змочувальна та мийна здатності поверхнево-активних речовин; вперше отримані ізотермічні залежності поверхневого натягу розчинів поверхнево- активних речовин різних класів. Практична значимість. Встановлені поверхнево-активні речовини та їх концентрації, що забезпечують найнижчі показники поверхневого натягу розчинів. [ABSTRACT FROM AUTHOR]

Aim. To investigate the effect of Nocardia vaccinii ІMV B-7405 surface-active substances (surfactants) on adhesion of some bacteria and yeasts to fragments urogenital silicone catheters. Methods. The degree of adhesion of microorganisms was determined as the ratio of the cells amount on treated by surfactants catheters fragments to the amount of cells in the control (without surfactant treatment) samples and expressed in percent. Cell concentration was determined by the method of Koch meat-peptone agar and glucose-potato agar. Results. It was shown that the attachment bacteria (Escherichia coli IEM-1, Erwinia sp. TБ-4, Enterobacter cloaceae AС-22, Pseudomonas sp. MI-2, Proteus vulgaris ПA-12) and yeast Candida albicans Д-6 to the fragments of urogenital silicone catheters treated with N. vaccinii IMB B-7405 surfactants depended on the concentration and purification of surfactants, and the type of test cultures. Treatment catheters of N. vaccinii IMB B-7405 surfactant (0.05–0.08 mg/ml) was accompanied by decrease adhesion of bacteria and yeast by 21–95% and 57–94%, respectively. Conclusions. Thus, N. vaccinii ІMB B-7405 surfactant can be used for development of effective preparations decreasing the adhesion of microorganisms on the surface of medical application.

Aim. To study the effect of divalent cations on NADP+-dependent glutamate dehydrogenase activity (key enzyme of biosynthesis of Nocardia vaccinii IMV B-7405 surface-active aminolipids) followed by appropriate modification of medium composition for synthesis of surfactants with high anti-adhesive and antimicrobial activity. Methods. The NADP+-dependent glutamate dehydrogenase activity (EC 1.4.1.4) in the cell-free extract was analyzed for the formation of glutamate in the oxidation of NADPH at 340 nm. Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1). Antimicrobial against bacteria and yeast properties of the surfactant was determined by index of the minimum inhibitory concentration (MIC). The number of attached cells was determined spectrophotometrically. Results. It was established that in the presence of 5−10 mM calcium cations NADP+-dependent glutamate dehydrogenase activity in the cell-free extract of N. vaccinii IMV B-7405 increased to 1.3−1.7 times in comparison with that without Ca2+. Increase from 0.1 to 0.4 g/l CaCl2×2H2O concentration in cultivation medium of IMV B-7405 strain was accompanied by rise of NADP+-dependent glutamate dehydrogenase activity in 1.5 times, as well as increasing antimicrobial and antiadhesive activity of synthesized surfactants. Minimum inhibitory concentration against some bacteria and yeasts surfactants synthesized in a medium with a heightened content of Ca2+ was in 1,8−13 times and adhesion test cultures on abiotic surfaces treated with such surfactants − an average of 7−39 % lower as compared to indicators for the surfactant produced in the base medium. Conclusions. The obtained results indicate the possibility of regulation of the antimicrobial and anti-adhesive activity of microbial surfactants with the change in cultivation medium of cations content - potential activators and/or inhibitors of key enzymes biosynthesis of surfactant components responsible for these biological properties. [ABSTRACT FROM AUTHOR]

Aim. To study the antimicrobial activity against some bacteria mixture of Nocardia vaccinii IMV B-7405 surfactants and antibiotics amikacin and ceftriaxone. Methods. Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2: 1).To determine the synergistic action antibiotics and surfactant solutions equal (0.5 mg/mL) concentrations were mixed in different proportions (20-80%, v/v). The antimicrobial activity of antibiotics, surfactants and their mixtures was determined by index of the minimum inhibitory concentration (MIC). Results. It was found that even in the presence of 50-80% surfactants in mixture with ceftriaxone and amikacin its MIC against Pseudomonas sp. MI-2, Staphylococcus aureus BMS-1, Enterobacter cloacae C-8 was on average 0,49-1,96 µg/ml, while the minimum inhibitory concentration of amikacin, ceftriaxone and surfactants separately was in the range 0.98-125 µg/ml. Conclusions. Lower MIC against bacterial test-cultures mixture of N. vaccinii IMV B-7405 surfactants and antibiotics as compared with minimum inhibitory concentration of individual preparations indicated their synergistic action. [ABSTRACT FROM AUTHOR]

Aim. To study the ability of surface-active agents (surfactants) synthesized Acinetobacter calcoaceticus IMV B-7241 on various substrates (ethanol, glycerol, n-hexadecane), destroy a biofilm certain bacteria and yeasts. Methods. Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2: 1). The degree of biofilm destruction was determined as difference between the number of adhered cells in untreated and treated with surfactant holes of polystyrene immunological plate containing pre-formed biofilm of test cultures and was expressed as a percentage. The number of adherent cells was determined by spectrophotometrically. Results. The dependence of degree of biofilms destruction in the presence of A. calcoaceticus IMV B-7241 surfactants on the nature of carbon source in medium of producer cultivation, concentration of surfactants in the preparations and test culture type was established. Degree of Escherichia coli IEM-1 biofilm destruction in the presence of surfactants synthesized on all tested substrates practically did not differ and was 25-53% depending on the concentration of the surfactants (0,04-1,28 mg/ml). Bacillus subtilis BT-2 biofilm destruction reached 71-86% after addition of surfactants (0,16-0,64 mg/ml) obtained on ethanol and glycerol. Maximum destruction of Staphylococcus aureus BMS-1 biofilm (69-88%) and Candida albicans D-6 (42%) was observed in the presence of surfactants (0,32-1,28 mg/ml) synthesized on n-hexadecane. Conclusions. The effective concentrations of A. calcoaceticus IMV B-7241 surfactants, providing a high degree of bacterial biofilms destruction are comparable to those of the known microbial surfactants. The obtained data indicates the need for research the influence of producer cultivation conditions on the biological properties of final product. [ABSTRACT FROM AUTHOR]

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To study the possibility of enhancement antimicrobial activity of the surfactants synthesized Nocardia vaccinii ІMV B-7405 after introduction into the medium Escherichia coli ІEM-1 and Bacillus subtilis BT-2.Methods. Live and inactivated cells of bacteria inductors (E. coli ІEM-1 and B. subtilis BT-2) were introduced into cultivation medium of surfactant producer at the beginning of the process and in the exponential growth phase. Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1). Antimicrobial against bacteria and yeast properties of the surfactant was determined by index of the minimum inhibitory concentration (MIC). Results. It has been established that introduction into cultivation medium of N. vaccinii ІMV B-7405 both live and inactivated E. coli ІEM-1 and B. subtilis BT-2 cells was accompanied by synthesis of surfactant with improved antimicrobial activity. The minimum inhibitory concentration against bacteria (E. coli ІЕМ-1, B. subtilis BТ-2, Pseudomonas sp. MІ-2, Proteus vulgaris PА-12) and yeast Candida albicans D-6 of surfactants synthesized in the presence of E. coli ІEM-1 and B. subtilis BT-2 were 6-50 μg/ml, that in 2,4-13 times lower than MIC of surfactant obtained in the medium without bacteria inductors. Conclusions. The data obtained indicate the possibility of regulation of antimicrobial activity of N. vaccinii ІMV B-7405 surfactants when cells of other bacteria including E. coli ІEM-1 and B. subtilis BT-2 were introduced into cultivation medium of surfactant producer. [ABSTRACT FROM AUTHOR]

Copyright of Eastern-European Journal of Enterprise Technologies is the property of PC TECHNOLOGY CENTER and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)