Abstract
The chemical compositions of phospholipids were comparatively examined for two acetic acid bacteria that produce acetic acid at high (20%) and moderate (12%) concentrations, i.e., Acetobacter polyoxogenes and Acetobacter sp., harvested at the stationary growth phase. Phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin (CL) were detected as the major phospholipids while CL was hardly present in A. polyoxogenes. PG was present in essentially the same amount in the microorganisms, and the level of PC in A. polyoxogenes was considerably higher (56%) than in A. sp. (37%). PE was significantly lower in A. polyoxogenes (11%) than in A. sp. (22%). High PC level in membranes may thus be considered due to resistance toward high concentrations of acetic acid that have accumulated in the medium. Phospholipid fatty acid compositions were basically the same for the two acetic acid bacteria, with cis-vaccenic acid being predominantly present at more than 80%. The amounts of unsaturated fatty acid components in the neutral phospholipids slightly exceeded those in the acidic phospholipids.
