Atmospheric nitrogen fixation by hydrocarbon‐oxidizing bacteria

Microorganisms have been found which concomitantly convert hydrocarbons, selected naphthenic acids, and atmospheric nitrogen into cellular substance. Bacteria are included in the genera Pseudomonas, Mycobacterium, and Azotobacter. Carbon sources utilized include the hydrocarbons methane, n‐butane, n‐tetradecane, toluene, and a naphthenic acid, cyclohexane‐carboxylate. Uptake of isotopic nitrogen was employed as a criterion of nitrogen fixation. The results indicate a rather wide prevalence in nature of hydrocarbon‐oxidizing bacteria capable of fixing atmospheric nitrogen. Their occurrence helps explain the high concentration of organic nitrogen commonly found in soils exposed to gas leakage from pipelines or natural‐gas seeps, and suggests further consideration of the possibility of applying selected petroleum residua to soils in order to increase the agricultural potential by nitrogen‐fixing processes.