Microbial Deterioration of Hydrocarbon Fuels from Oil Shale, Coal, and Petroleum. II. Growth and Inhibition of Bacteria and Fungi

摘要

The recurring problems caused by microbial contamination of conventional fuels has led to an evaluation of the susceptibility of aircraft fuels from alternate sources (synthetic fuels). JP-5 fuel from coal and two different lots of oil shale (Shale I and II) were studied. Shale I differed from Shale II in having a much higher nitrogen content. Anaerobic, sulfate-reducing bacteria were able to grow as well with JP-5 from coal and oil shale as with petroleum. In fungal susceptibility tests with four different strains of Cladosporium resinae and one Candida sp., Shale II supported good fungal growth while Shale I did not; coal was highly inhibitory. The inhibition caused by Shale I was traced to the alkalinity produced by basic, nitrogen-containing extractables in this fuel, but coal contains specific, still unidentified inhibitory constituents. It was also found that the normally high pH of seawater media was sufficient to inhibit C. resinae. Growth which occasionally occurred in seawater/fuel systems was apparently due to establishment of reduced pH in a local microenvironment. (Author)