Emulsification activity was measured according to Cooper and
Goldenberg (1987). Briefly, 5 ml of hexane were added to 5 ml
culture supernatant and then agitated with vortex at high speed for
2 min. The mixture was then allowed to stand still for 24 h (EA24)
prior to measurement. Emulsification activity was defined as the
height of the emulsion layer divided by the total height and
expressed as percentage.