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Poster Presentation 2-29
The Regulation of C2-Metabolism in the Acinetobacter sp. Strain Producing Exopolysaccharide Ethapolan
T.P.Pirog, Yu.V.Kuzminska, M.A. Kovalenko
Ukrainian Academy of Sciences, Institut of Microbiology and Virology 154 Zabolotny St., 03143, Kiev, Ukraine
Telephone: 380 44 266 99 69; Fax: 380 44 266 23 79; E-mail: tapirog@usuft.kiev.ua
The activities of the key enzymes of ethanol metabolism were determined in the growth on ethanol cells of the Acinetobacter sp. strain-producing exopolysaccharide (EPS) ethapolan. Ethapolan is the new polysaccharide for the oil industry.
The ethanol oxidation to acetaldehyde in Acinetobacter sp. was determined to be catalyzed by NAD+-dependent alcohol dehydrogenase (EC 1.1.1.1.). The electron acceptors in acetaldehyde degydrogenase reaction were NAD+ and NADP+. Acetate was introduced into the Acinetobacter sp. metabolism by acetyl-CoA-synthetase (EC 6.2.1.1.). The presence of isocitrate lyase (EC 4.1.3.1.) testified that the glyoxylate cycle was caused by the anaplerotic reactions filling up the pool of the C4-dicarbonic acids in the Acinetobacter sp. cells.
The introduction of acetate into the Acinetobacter sp. metabolism was the “bottle-neck” of the ethanol metabolism in these bacteria: the reaction catalyzed by acetyl-CoA-synthetase was rate-limited. The inhibitors of acetyl-CoA-synthetase were shown to be the sodium cations and the products of the ethanol and acetaldehyde oxidation (NADH & NADPH). The activators of this enzyme were determined to be pantothenic acid, the potassium and magnesium cations.
The conditions of the Acinetobacter sp. cultivation were determined allowing for the equal oxidation rate of ethanol, acetaldegyde and acetate in the intact cells and also to increase the acetyl-CoA-synthetase activity in the free-cell extracte.
The regulation investigations of the acetyl-CoA-synthetase activity in the Acinetobacter sp. are the basis of development of new technology in ethapolan production on ethanol.
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