Growth of Cupriavidus eutrophus B-10646, fatty acid (FA) composition of the lipids in the cytoplasmic membrane and cell wall, and polyhydroxyalkanoate (PHA) accumulation by the cells of this new promising producer of PHAs were studied in batch culture, using various carbon sources (fructose, glucose, oleic acid, sunflower seed oil, glycerol, CO2:O-2:H-2). In cells grown on sugars and in autotrophic culture, during the phase of active cell growth, the major FAs of the lipids of cytoplasmic membrane (CMLs) were palmitic, palmitoleic, and cis-vaccenic acids. In the stationary phase of cultivation, cyclopropane FAs were also detected. When carbohydrate substrate was replaced by oleic acid or sunflower seed oil, the proportion of oleic acid in the total FAs of the cytoplasmic membrane increased considerably. In addition to that, the lipid FAs of bacterial cells grown on sunflower seed oil also contained linoleic acid, which is the major acid of sunflower seed oil. The major acids of strongly bound lipids of cell wall (SBLs) were myristic acid and long-chain-length beta-hydroxy acids. Molecular weight of the polymer was measured during its accumulation in cells; for the first time, the presence of 2 polymer fractions (high-molecular weight and low-molecular-weight ones) was recorded in cells with a low polymer content. (C) 2014 Elsevier Ltd. All rights reserved.