TABLE 2.

Chemical composition data (as determined by XPS) for S. mitis BMS and BA biosurfactants released in the stationary growth phase and for reference compounds

Crude biosurfactant or compound	Elemental concn ratios			Fractions of carbon and oxygen involved in various chemical functions
	N/C	O/C	P/C	C—(C,H)	C—(O,N)	C⩵O	O⩵C—OH	(O⩵C)/C	(OH)/C
Biosurfactant released by:
S. mitis BA	0.172	0.407	0.019	0.58	0.24	0.18	0	0.342	0.065
S. mitis BMS	0.101	0.426	0.016	0.64	0.20	0.13	0.04	0.268	0.158
Acid-precipitated S. mitis BMS biosurfactant	0.071	0.366	0.016	0.61	0.24	0.11	0.05	0.121	0.244
Reference compounds
Proteina	0.270	0.32	0	0.41	0.32	0.28f		0.275	0.045
Glycosidic residueb	0	0.83	0	0	0.83	0.17f		0	0.833
Rhamnolipid R1c	0	0.406	0	0.56	0.31	0.06	0.06	0.061	0.345
Rhamnolipid R2c	0	0.346	0	0.65	0.23	0.04	0.08	0.076	0.269
Phospholipidd	0.009	0.21	0.034	0.82	0.13	0.05	0.01	0.077	0.132
LTAe	0.031	0.63	0.066	0.41	0.44	0.44	0.10	0.151	0.478

^aAverage protein, calculated based on a collection of bacterial, fungal, and mammalian proteins (21). 

^bGlycosidic residue C₆H₁₀O₅ (21). 

^cCalculated for rhamnolipids synthesized by Pseudomonas aeruginosa. R1 contains two rhamnose units, and R2 contains one rhamnose unit (6, 11). 

^dl-α-Phosphatidyl-dl-glycerol dimyristoyl. 

^eLTA, Lipoteichoic acid from S. mutans (Sigma). 

^fC⩵O and O⩵C—OH together.