Emulsifying capacities were determined by the addition, into screw cap tubes, of
equal volumes of cell free fermentation media and selected hydrocarbons: hexane,
jet fuel (KAV) and Arabian light crude-oil. Screw cap tubes were mixed using a
vortex for 2 min, and leaving to rest for 24 h at 29 1 8C. The emulsification indexes
(E24) were determined as the percentage of the height of the emulsion columns.