Перегляд за Автор "Votselko, S."

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A method for determining the mass-molecular composition of microbial exopolysaccharides
(1993) Votselko, S.; Pirog, Tatiana; Malashenko, Yuri; Grinberg, Tamara
A method of determining the molecular mass composition of microbial exopolysaccharides (EPS) by centrifuging them in a combined density gradient created by NaCl and CsCl solutions and using the molecular mass of dextranes as standards is developed. The process of determining the molecular mass distribution pattern of EPS is simplified and made considerably less time-consuming. This method allows the analysis of native EPS with molecular masses ranging from 13 700 to 2 000 000.
A two-stage cultivation technique for producing microbial exopolysaccaride ethapolan with improved rheological properties
(2001) Pirog, Tatiana; Malashenko, Yuri; Votselko, S.
A two-stage technique was proposed for cultivating producers of microbial exopolysaccharide ethapolan. The practical value of ethapolan is determined by its rheological properties. The use of a formaldehyde-supplemented medium at the second stage of cultivation improved the rheological properties of ethapolan without reducing its yield. This effect of formaldehyde was due to its binding to the exopolysaccharide, which altered the molecular-weight characteristics of the latter and protected cells against the toxic action of formaldehyde. At all stages of its purification, ethapolan had improved rheological properties, suggesting that it was tightly bound to formaldehyde.
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.