Original Articles
Mohammed EL Amine Bendaha, Bou
Abstract
Thirty bacterial strains were isolated from soils c ontaminated with hydrocarbons in the north west of Algeria, and tested for biosurfactants production in a nutrient broth supplemented with olive oil using drop collap sing, oil displacement, emulsification activity (E 24 ) and measurement of the surface activity. S1PS2, S 7PS5 and S9PS2 strains were the best three producers and were sel ected to optimize the production (S1PS2 : E 24 = 56.32 ± 1.95%, Ø = 5.733 ± 0.35 cm and % Reduction = 30.17 ± 0.12, S7PS5 : E 24 = 43.38 ± 0.07%, Ø = 8.3 ± 0.10 cm and % Reduction = 31.23 ± 0.01, S9PS2 : E 24 = 44.27 ± 0.26%, Ø = 8.66 ± 0.05 cm and % Reduction = 32.00 ± 0.13). After optimization, S7PS5 shows the optimal of rhamnolipids production with the following composition: 100 ml of nutrient broth, 1% of olive oil and 1% of inoculums, with shaking at 7 5 rpm/min at room temperature, for an incubation pe riod of 22 h, and it was selected for an identification using API 20NE system and 16S rDNA sequencing which allowed the link S7PS5 to the genus Pseudomonas and showed 98.84% of similarity with Pseudomonas aeruginosa LMG 1242 T /Z76651 as the closest specie.