Influence of residual ethanol concentration on the growth of Gluconacetobacter xylinus I 2281

• Published in: Applied microbiology and biotechnology Vol. 62; no. 2/3; pp. 168 - 173
• Main Authors: Kornmann, H, Duboc, P, Niederberger, P, Marison, I, Stockar, U. von
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01-08-2003; Springer Nature B.V
• Subjects: Acetate Kinase - metabolism; Acetate-CoA Ligase - metabolism; acetates; Acetic acid; acetic acid bacteria; Acetobacteraceae - drug effects; Acetobacteraceae - growth & development; Acetobacteraceae - metabolism; acetyl coenzyme A; Bacteria; Biological and medical sciences; biomass; Bioreactors; Biotechnology; Carbon; Carbon dioxide; Citric Acid Cycle; Culture Media; Ethanol; Ethanol - metabolism; Ethanol - pharmacology; Food Microbiology; Fundamental and applied biological sciences. Psychology; Gluconacetobacter xylinus; Glucose; Glucose - metabolism; Glycolysis; Kinetics; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; microbial growth; Microbiology; Models, Biological; Molecular microbiology; Observations; oxidation; Phosphate Acetyltransferase - metabolism; Proteobacteria; Switzerland; Microorganism culture; Bacteria; Ethanol; Metabolism; Growth; Concentration effect
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-003-1299-2

The influence of residual ethanol on metabolism of food grade Gluconacetobacter xylinus I 2281 was investigated during controlled cultivations on 35 g/l glucose and 5 g/l ethanol. Bacterial growth was strongly reduced in the presence of ethanol, which is unusual for acetic acid bacteria. Biomass accumulated only after complete oxidation of ethanol to acetate and carbon dioxide. In contrast, bacterial growth initiated without delay on 35 g/l glucose and 5 g/l acetate. It was found that acetyl CoA was activated by the acetyl coenzyme A synthetase (Acs) pathway in parallel with the phosphotransacetylase (Pta)-acetate kinase (Ack) pathway. The presence of ethanol in the culture medium strongly reduced Pta activity while Acs and Ack remained active. A carbon balance calculation showed that the overall catabolism could be divided into two independent parts: upper glycolysis linked to glucose catabolism and lower glycolysis liked to ethanol catabolism. This calculation showed that the carbon flux through the tricarboxylic cycle is lower on ethanol than on acetate. This corroborated the diminution of carbon flux through the Pta-Ack pathway due to the inhibition of Pta activity on ethanol.