3.5. Characterization of USTBa biosurfactant
3.5.1. Physicochemical characterization of biosurfactant
The biosurfactant produced by Bacillus sp. USTBa was a glycolipid
comprising 32% (w/w) carbohydrate and 64% (w/w) lipid on
a dry weight basis. The unique ionic strength tolerance of biosurfactant
renders its prospective use for oil-related applications
where always high saline condition prevails [23]. Fig. 5A depicts
the agar double diffusion test of the biosurfactant produced by B.
methylotrophicus USTBa. A precipitation line is observed between
the biosurfactant and trimethylammonium bromide (a cationic
surfactant); whereas no line is formed between the biosurfactant and SDS (an anionic surfactant). This test indicates the anionic
character of the bio surfactant which is similar to other biosurfactants
produced from different microorganisms [12,35].