Oils, fixed nitrogenated

The biodegradation of crude oils in their reservoirs is well documented (M, 22). It occurs in the presence of meteoric water which supplies dissolved oxygen and nutrients including phosphate and fixed nitrogen. Microenvironments may exist in which aerobic and anaerobic activities occur in close proximity so that intermediates of aerobic metabolism may become substrates for anaerobic bacteria. In reservoirs, microbes are most active at the oil-water interface and at temperatures between about 20° and 60 to 75°C. 

AH fixed oils consist essentially of these three elements only, some, however, yield minute truces of nitrogen, referable to adhering impurities. 

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