Перегляд за Автор "Grinberg, Tamara"

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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.
Effect of environmental factors on the synthesis and properties of Acinetobacter sp. exopolysaccharides
(1998) Pirog, Tatiana; Grinberg, Tamara; Malashenko, Yuri
Effects of external factors on the synthesis and physicochemical properties of Acinetobacter sp. exopolysaccharides (EPSs), which determine the biological functions of this microorganism, were studied. The cultivation temperature, medium pH, and oxygen concentration in the medium (p02) affected the viscosity of EPS solutions in the presence of monovalent cations, in the H+-form, and in a Cu2+-glycine system. All the EPSs studied were precipitated with heavy metal ions (Cr3+, Cu2+, Pb2+, Cd2+, etc.). No changes in the EPS yield were observed under unfavorable environmental conditions. At high pO2 values (up to 80% of saturation), the maximum specific rates of bacterial growth and EPS synthesis increased. It was suggested that Acinetobacter sp. EPSs perform different biological functions under optimal and nonoptimal conditions.
Ethapolan: a new microbial exopolysaccharide for oil industry
(1995) Grinberg, Tamara; Pirog, Tatiana; Malashenko, Yuri; Vlasov, Sergei A.
Ethapolan, a new high-viscous exopolysaccharide, was obtained in the course of microbial synthesis. Its chemical content and some characteristics of its solutions are explored in the present study. By its structure ethapolan may be considered a polysaccharide of xanthan type. More definitely, as compared to xanthan, the emulsifying efficiency and hydrophobic nature of ethapolan may be attributed to the presence of the fatty acids residues and to 6-desoxysaccharide—rhamnose residues. It was found that a few factors impact the increasing viscosity of ethapolan solutions: first, the presence of the cations; second, low shearing rates; and, finally, low pH values. Ethapolan is resistant to heating. On this basis, it may be concluded that ethapolan appears to be a universal and quite competitive microbial exopolysaccharide for the oil industry.
Search for methanotrophic producers of exopolysaccharides
(2001) Malashenko, Yuri; Pirog, Tatiana; Romanovska, V.; Malashenko, Yuri; Sokolov, I.; Grinberg, Tamara
Bacteria that produce exopolysaccharides (EPS) and use methane as the only source of carbon were selected by studying a collection of methanotroph strains: Methylococcus capsulatus E 494, 874, and 3009; M. thermophilus 111p, 112p, and 119p; Methylobacter ucrainicus 159 and 161; M. luteus 57v and 12b; Methylobacter sp. 100; Methylomonas rubra 15 sh and SK-32; Methylosinus trichosporium OV3b, OV5b, and 4e; M. sporium 5,12, A20d, and 90v; and Methylocystis parvus OVVP. Mesophilic methanotroph strains with the ribulose monophosphate way of C1-compound assimilation synthesized EPS more actively than bacteria operating the serine cycle. The dynamics of EPS synthesis by methanotrophs during chemostat cultivation was studied.