Table 2.

Demulsification percentage of motor oil emulsions in distilled water and in sea water after addition of biosurfactants

Microorganisms	Biosurfactant concentration	Demulsification of motor oil (%)a
		Oil-in-water (O/W) emulsions
		Distilled water	Sea water
C. sphaerica	Cell-free broth	39.0 ± 0.9	40.6 ± 0.5
	½ CMC	35.0 ± 0.9	38.2 ± 0.6
	CMC	36.9 ± 0.7	38.4 ± 0.7
	2 × CMC	37.0 ± 0.9	39.4 ± 0.8
C. lipolytica (a)	Cell-free broth	30.0 ± 0.9	36.0 ± 0.9
	½ CMC	37.9 ± 0.4	37.0 ± 0.9
	CMC	37.0 ± 0.9	42.4 ± 0.8
	2 × CMC	35.7 ± 0.3	43.0 ± 0.9
C. lipolytica (b)	Cell-free broth	27.3 ± 0.7	26.9 ± 0.9
	½ CMC	27.0 ± 0.6	27.0 ± 0.9
	CMC	27.0 ± 0.9	26.7 ± 0.6
	2 × CMC	27.0 ± 0.5	27.3 ± 0.5
C. guilliermondii	Cell-free broth	31.7 ± 0.9	44.9 ± 0.9
	½ CMC	40.0 ± 0.7	40.7 ± 0.4
	CMC	42.6 ± 0.3	44.6 ± 0.9
	2 × CMC	42.1 ± 0.9	41.0 ± 0.9
P. cepacia	Cell-free broth	30.6 ± 0.7	39.0 ± 0.9
	½ CMC	34.0 ± 0.9	45.0 ± 0.9
	CMC	43.3 ± 0.7	37.5 ± 0.5
	2 × CMC	43.8 ± 0.5	65.0 ± 0.9
Bacillus sp.	Cell-free broth	42.0 ± 0.9	37.0 ± 0.9
	½ CMC	46.6 ± 0.9	40.0 ± 0.8
	CMC	47.0 ± 0.9	54.4 ± 0.9
	2 × CMC	60.1 ± 0.8	66.0 ± 0.9
P. aeruginosa	Cell-free broth	44.0 ± 0.5	50.0 ± 0.6
	½ CMC	21.2 ± 0.4	29.1 ± 0.8
	CMC	48.0 ± 0.9	50.0 ± 0.9
	2 × CMC	62.0 ± 0.9	65.7 ± 0.6

Results are expressed as mean ± pure error

^aControl values for the demulsification in the absence of biosurfactants were less than 5%