An enrichment culture procedure has been used to isolate mixed culture systems which grow upon “Bunker C” fuel oil. When inoculated into a mineral salts aqueous medium containing Bunker C oil, the mixed cultures initiate oil emulsification. Emulsification usually is observed in 24–48 hr. The role of microbes in this emulsification will be discussed. It appears that certain metabolic products produced by the microbe possess properties of surfactants. Bacteria and fungi have been isolated which possess the ability to cause emulsification. Freeze‐dried biomass is also capable of emulsifying oil. Chromatographic analyses of biodegraded Bunker C fuel oil show that microorganisms selectively metabolize the n‐paraffin fraction.

The bacterial cultures were isolated from sewage which removed almost completely the paraffinic components from Grade 6 fuel oil (Bunker C oil). Of the major components in fuel oil, only the saturate fraction decreases during biodegradation. These microbes, particularly culture B2, produce a very active emulsifying agent for Grade 6 fuel oil. This emulsifier is synthesized from the paraffinic components in the fuel oil. Oil globules are 3-16µ size. This emulsifier appears to be a high-molecular-weight polysaccharide. Low temperatures and high salt levels tend to