Biosurfactant production from pseudomonas strains isolated in rhizospheric soils from semi-arid area of Bahia, Brazil

The aim of this study was to select biosurfactant-producing bacterial strains from soils of plants in the semi-arid region of the state of Bahia, Brazil. The mineral salt medium (MSM) was used as base medium, changes being made in the glucose concentration, temperature, and pH during the optimization process. Two biosurfactant-producing bacterial strains were isolated from the soil of Actinocephalus sp. and belonged to the genus Pseudomonas . The emulsification indexes of these strains rose until 58%. They reduced surface and interfacial tensions of culture medium and crude oil to less than 33 mN/m and 3 mN/m, respectively. This study represented an unprecedented discovery of surfactant activity of the bacterial strains isolated from rhizospheric soils of plants from Northeast Brazilian semi-arid region.