Aerobic stepwise hydrocarbon degradation and formation of biosurfactants by an original soil population in a stirred reactor

Summary Using a model system containing 10% soil and a 1.35% hydrocarbon mixture of tetradecane, pentadecane, hexadecene, pristane (2,6,10,14-tetramethylpentadecane), trimethylcyclohexane, phenyldecane and naphthalene suspended in a mineral salts medium, the hydrocarbon degradation rate by a soil population was 25.7 g model oil per kg soil dry weight per day under non-limited conditions within two degradation phases. During the first degradation phase only the most water-soluble naphthalene was degraded, while the other components could only be metabolized when the interfacial tension was lowered by the production of surfactants at the beginning of the second degradation phase. This second degradation phase ended when 89% of the hydrocarbons were metabolized.Dedicated to Professor F. Wagner on the occasion of his 60th birthday