MICROBIAL DEGRADATION OF A LOUISIANA CRUDE OIL IN CLOSED FLASKS AND UNDER SIMULATED FIELD CONDITIONS

Abstract

ABSTRACT Petroleum utilizing microorganisms in flasks containing enriched seawater exhibited a clear metabolic preference for saturated paraffins in a Louisiana crude oil. The rates of oxidation of these compounds were directly proportional to incubation temperature and roughly doubled with a ten degree increase. A pattern of growth consisting of an initially large rate of saturated paraffin oxidation, followed by a decrease and another increase in rate was observed. The initially large rates were attributed to the metabolism of n-paraffins smaller than C-18. No even or odd chain length preference for n-paraffins was indicated. There was no evidence of utilization for aromatic compounds. Application of a microbial culture to an oil slick under simulated field conditions, clearly showed that microbes could accelerate the removal of a Louisiana crude oil from an oil slick on seawater. The rates of oil removal in outdoor, exposed conditions, were twice as large as the rates of evaporative oil loss. The microbes produced a significant change in oil “stickiness”. Measurements indicated the oil was dispersed through microbial activity. The cells preferentially remained at the oil-water interface during the experimental periods.