Microbial Degradation of a Louisiana Crude Oil in Closed Flasks and Under Simulated Field Conditions

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.

Stimulated biodegradation of oil slicks using oleophilic fertilizers

“…Oil that escapes from the containment may be mistakenly considered as "degraded." Some workers have used stagnant sea water tanks of various sizes (Gunkel, 1967;Kator et al, 1971) but this experimental design limits the amount of available sea water. Quantitative and representative sample removal for analysis in the systems described above is very difficult (Kator et al, 1971).…”

“…Some workers have used stagnant sea water tanks of various sizes (Gunkel, 1967;Kator et al, 1971) but this experimental design limits the amount of available sea water. Quantitative and representative sample removal for analysis in the systems described above is very difficult (Kator et al, 1971). We believe that our experimental design with flow-through sea water and individual sample tubes solved some of these difficulties and may prove useful in future studies of similar nature.…”

Degradation and mineralization of petroleum by two bacteria isolated from coastal waters

“…The relative recalcitrance of pristane and its value as internal st'andard has also been report.ed by ot.her ~v o r k e r s . '~*~~ The possible use of hydrocarbon utilizing microorganisms for accerlerated degradation of accidentally spilled oil is receiving serious c~nsideration.~ IIiget' et al 17 and Kator et al 15 have studied the effectiveness of-mixed marine enrichment cultures for this purpose. There is no doubt that mixed enrichments can degrade a highly complex substrate such as petroleum more effectively than any single microorganism, but the practical use of an enrichment of unknown composition is likely to encounter licensing difficulties because of its potential side effects on marine life.…”

Hydrocarbon Biodegradation and Oil Spill Bioremediation

“…Veryhigh-molecular-weight aromatics, resins, and asphaltenes are considered to be recalcitrant or exhibiting only very low rates of biodegradation, but some studies have reported the biodegradation of some of the higher-molecular-weight aromatic and asphaltene compounds in petroleum (Leahy and Colwell, 1990). The n-alkanes are readily degraded and usually considered the most readily degraded compounds in petroleum (Davies and Hughes, 1968;Kator et al, 1971;Kator and Herwig, 1977;Treccani, 1964;ZoBell, 1946). Biodegradation of n-alkanes with molecular weights up to n-C 44 have been demonstrated (Haines and Alexander, 1974).…”