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Документ Factors affecting antibiofilm properties of microbial surfactants(2021) Pirog, Tatiana; Kliuchka (Nykytyuk), Lilia; Lutsay, Dariya; Stabnikov, VictorAntibiofilm activity of surface-active substances (SAS) synthesized by Rhodococcus erythropolis, Acinetobacter calcoaceticus, or Nocardia vaccinia was studied. The strains were cultivated using carbon ethanol, glycerol, hexadecane, sunflower oil, and carbon-containing wastes from biodiesel production as carbon sources. Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and yeasts Candida albicans and Candida utilis were used as testing cultures. The antibiofilm activity of biosurfactants depended on the source and concentration of carbon source and duration of cultivation. The addition of calcium cations to media significantly increased antibiofilm activity. Replacement of pure sources of carbon for wastes provided the opportunity to receive biosurfactants with high antibiofilm properties on inexpensive substrates. Destruction of biofilms was the same in cases when supernatant or purified SAS was used. Вивчено антибіоплівкову активність поверхнево-активних речовин (ПАР), синтезованих Rhodococcus erythropolis, Acinetobacter calcoaceticus або Nocardia vaccinia. Штами культивували з використанням в якості джерел вуглецю вуглецевого етанолу, гліцерину, гексадекану, соняшникової олії та вуглецевмісних відходів виробництва біодизеля. Як тест-культури використовували Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, дріжджі Candida albicans і Candida utilis. Антибіоплівкова активність біосурфактантів залежала від джерела та концентрації джерела вуглецю та тривалості культивування. Додавання до середовищ катіонів кальцію значно підвищувало активність антибіоплівки. Заміна чистих джерел вуглецю на відходи дала можливість отримувати на недорогих субстратах біоПАР з високими антибіоплівковими властивостями. Деструкція біоплівок була однаковою у випадках використання супернатанту або очищеного ПАР.Документ The influence of culture conditions strain Acinetobacter calcoaceticus K-4 on the synthesis of surfactant(2009) Pirog, Tatiana; Karpenko, Elena; Antoniuk, Svitlana; Shevchuk, TetianaIt has been observed that the Acinetobacter calcoaceticus K-4 strain produces surface-active substances (SAS) while growing either on hydrophilic (ethanol) or on hydrophobic substrates (hexadecane). Maximal SAS synthesis (with a conditional SAS concentration of 3.6; emulsifying activity of culture liquid dissolved in 50 times equal to 96%) was detected with growth on an ethanol-containing medium with the addition of urea, yeast autolysate and microelements, C/N ratio 60:1 and 10% inoculate, cultivated on ethanol-containing medium by the end of the exponential phase of growth. With respect to its chemical nature, extracellular SAS synthesized by A. calcoaceticus K-4 growing on ethanol-containing medium under optimal cultivating conditions form a glycolipid–aminolipid complex.Документ The influence of culture conditions on the physico-chemical properties of exopolysaccharide etapolana(2009) Pirog, Tatiana; Korzh, Yuliya; Shevchuk, TetianaThe physicochemical properties of the complex exopolysaccharide ethapolan (EPS) produced by Acinetobacter sp. 12S during growth on media with various C/N ratios and different concentrations of mineral components and phosphate buffer were studied. Irrespective of the cultivation conditions, the concentrations of carbohydrates (38–44%) and pyruvic acid (3.2–3.7%) in the total EPS, as well as in the acylated (AP) and nonacylated (NAP) polysaccharides obtained from them, were practically the same. The EPS, AP, and NAP were also identical in their monosaccharide composition: the molar ratio of glucose, mannose, galactose, and rhamnose was 3 : 2 : 1 : 1. The polysaccharides contained different concentrations of mineral salts (6–28%), uronic acid (3.7–22.0%), and fatty acids (5.8–15.4%); they also differed in the ratio of acetylated and nonacetylated polysaccharides. Due to the differences in the chemical composition and molecular mass (500 kDa – 1.5 MDa), the viscosities of the EPS solutions (in the presence of 0.1 M KCl, in the H+–form, and in Cu2+–glycine system) were different as well. The mechanisms responsible for changes in the physicochemical properties of the total EPS, AP, and NAP synthesized on various media are discussed.Документ Physicochemical Properties of the Microbial Exopolysaccharide Ethapolan Synthesized on a Mixture of Growth Substrates(2004) Pirog, Tatiana; Kovalenko, M.; Kuzminska, Yu.; Votselko, S.Some physicochemical properties of the microbial exopolysaccharide (EPS) ethapolan synthesized by Acinetobacter sp. 12S depended on whether the producer was grown on a mixture of ethanol and glucose or on a single substrate. Irrespective of the carbon source in the nutrient medium, the contents of carbohydrates, pyruvic acid, uronic acids, and mineral components in the EPS remained unchanged. The EPS were also identical in their monosaccharide composition: the molar ratio of glucose, mannose, galactose, and rhamnose was 3 : 2 : 1 : 1. EPS with a higher content of fatty acids was synthesized during growth on the mixture of ethanol and glucose. The average molecular mass and the content of high-molecular (M > 2 MDa) fractions were greater in ethapolan produced on the substrate mixture. In the presence of 0.1 M KCl, after transformation into the H+ form, and in the Cu2+–glycine system, solutions of these EPS showed higher viscosity than solutions of EPS synthesized on single substrates. The reasons for the improved rheological properties of the EPS produced on the substrate mixture are discussed.