Microbial Degradation of Cycloparaffinic Hydrocarbons via Co-metabolism and Commensalism

Summary: Mineralization of a cycloparaffinic hydrocarbon in soil has been demonstrated. Addition of [U-14C]cyclohexane to marine mud, followed by incubation at 26 °C, resulted in the evolution of 14CO2. All attempts in our laboratory to isolate organisms from soil which utilize cycloparaffins as a sole source of carbon and energy have proved unsuccessful. However, several hydrocarbon-utilizing bacteria oxygenated cycloparaffins to ketone derivatives that serve as the energy and carbon source for numerous other soil micro-organisms. The concerted attack of a mixed microbial population on cyclohexane has been demonstrated, suggesting that both co-metabolism and commensalism are associated with microbial degradation of cycloparaffinic hydrocarbons.