[Peculiarities of ethanol metabolism in an Acinetobacter sp. mutant strain defective in exopolysaccharide synthesis].
Activities of the key enzymes of ethanol metabolism were assayed in ethanol-grown cells of an Acinetobacter sp. mutant strain unable to synthesize exopolysaccharides (EPS). The original EPS-producing strain could not be used for enzyme analysis because its cells could not to be separated from the extremely viscous EPS with a high molecular weight. In Acinetobacter sp., ethanol oxidation to acetaldehyde proved to be catalyzed by the NAD(+)-dependent alcohol dehydrogenase (EC 1.1.1.1.). Both NAD+ and NADP+ could be electron accepters in the acetaldehyde dehydrogenase reaction. Acetate is implicated in the Acinetobacter sp. metabolism via the reaction catalyzed by acetyl-CoA-synthetase (EC 6.2.1.1.). Isocitrate lyase (EC 4.1.3.1.) activity was also detected, indicating that the glyoxylate cycle is the anaplerotic mechanism that replenishes the pool of C4-dicarboxylic acids in Acinetobacter sp. cells. In ethanol metabolism by Acinetobacter sp., the reactions involving acetate are the bottleneck, as evidenced by the inhibitory effect of sodium ions on both acetate oxidation in the intact cells and on acetyl-CoA-synthetase activity in the cell-free extracts, as well as by the limitation of the C2-metabolism by coenzyme A. The results obtained may be helpful in developing a new biotechnological procedure for obtaining ethanol-derived exopolysaccharide ethapolan.
Pirog
T P
TP
Zabolotnyi Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kiev, Ukraine. pirog@serv.imv.kiev.ua
Sokolov
I G
IG
Kuz'minskaia
Iu V
IuV
Malashenko
Iu R
IuR
D000079:Acetaldehyde / Q000378:metabolism; D000106:Acetate-CoA Ligase / Q000032:analysis / Q000378:metabolism; D000085:Acetates / Q000378:metabolism; D000150:Acinetobacter / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000032:analysis / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D007522:Isocitrate Lyase / Q000032:analysis / Q000378:metabolism; D009154:Mutation; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000235:genetics
D000085:Acetates; D011135:Polysaccharides, Bacterial; D000431:Ethanol; D000429:Alcohol Oxidoreductases; C084155:alcohol dehydrogenase (NAD(P)+); D007522:Isocitrate Lyase; D000106:Acetate-CoA Ligase; D000079:Acetaldehyde