A MODEL FOR DIFFUSION-CONTROLLED BIOAVAILABILITY OF CRUDE-OIL COMPONENTS

Crude oil is a complex mixture of several different structural classes of compounds including alkanes, aromatics, heterocyclic polar compoun ds, and asphaltenes. The rate and extent of microbial degradation of c rude oil depends on the interaction between the physical and biochemic al properties of the biodegradable compounds and their interactions wi th the non-biodegradable fraction. In this study we have systematicall y altered the concentration of non-biodegradable material in the crude oil and analyzed its impact on transport of the biodegradable compone nts of crude oil to the microorganisms. We have also developed a mathe matical model that explains and accounts for the dependence of biodegr adation of crude oil through a putative bioavailability parameter. Exp erimental results indicate that as the asphaltene concentration in oil increases, the maximum oxygen uptake in respirometers decreases. The mathematically fitted bioavailability parameter of degradable componen ts of oil also decreases as the asphaltene concentration increases.