Membrane Components and Cell Form of Acetobactor polyoxogenes (Vinegar Producing Strain) under High Acidic Conditions

Membrane components and cell form of A. polyoxogenes (vinegar producing strain) under high acidic conditions were studied. A. polyoxogenes was inoculated in the medium containing 6% of acetic acid, and the culture was continued until the acetic acid concentration in the medium reached to 8, 12 and 19%. Composition of phospholipid component in the microbe membrane varied with an increase in the acetic acid concentration in the medium. The ratio of phosphatidylcholine increased and that of phosphatidylglycerol decreased as the acetic acid concentration increased. The ratio of phosphatidylethanolamine was little affected. Cardio-lipin was not detected during the fermentation period. Ratio of unsaturated fatty acid in the total lipid was very high, and 86% of the total lipid was cis-vaccenate and its ratio was almost identical through the fermentation. Proteins of A. polyoxogenes cell collected from the broth at several fermentation stages were analyzed by electrophoresis. Some differences were observed among proteins from soluble fractions but not among proteins from membrane fractions containing the enzymes of acetic acid fermentation. SEM of cells of A. polyoxogenes harvested at each acidity showed that the cell obtained at 8 and 12% acetic acid concentration looked much shrinking and the cell obtained at 19% acetic acid concentration looked a normal form. These observations suggest that cell wall also changed with acetic acid concentration. In conclusion, membrane component ratio and cell wall structure of A. polyoxogenes changed according to change of acetic acid concentration in the broth.