A study of the kinetics of microbial oxidation of hydrocarbons was carried out using a one organism-pure hydrocarbon system (Pseudomonas aeruginosa-heptane). In batch culture, heptane supply is growth limiting at a cell concentration of 3 g/l on a dry basis. The cell concentration was increased to 8 g/l when heptane was volatilized in the influent air to increase interfacial area and mass transfer. Specific growth rate is increased by temperature more than can be accounted for by the effect of temperature alone on growth rate. The effect is attributed to the higher solubility of heptane at the higher temperature. Wash-out characteristic of continuous cultures on heptane differ from the theoretical and is explained on the basis of mass transfer limitations. Steady-states are possible at dilution rates higher than those predicted from batch cultures. Productivity was found to be 1.5 g/l/hr at D=0.26 with a heptane feed rate of 18 ml/hr. Limitation of magnesium or iron in the heptane limited cultures resulted in a marked increase in heptanoic acid production; heptane growth cells had a markedly higher lipid content than those grown on glucose. (Author)