การผลิตสารลดแรงตึงผิวชีวภาพจากแบคทีเรีย were isolated from soil samples contaminated with petroleum hydrocarbons. Isolates were screened for biosufactant production using Cetyl Tri Ammonium Bromind (CTAB) – Methylend blue agar selection medium . A candidates bacterial strain was selected for further studies based on surface tension reduction capacity and rapid drop collapse activity. Biochemical characteristics and partially sequenend 16S rRNA gene of the isotate, 5B, identified the bacterium as Bacillus clausii.
Different carbon and nitrogen sources were evaluated for their effect on biosurfactant production.
Maximum biosurfactant systhesis (2.11 g/L) was observed at 96 hours when the cells were grown on minimal medium containing 1 % glucose as carbon source. Amomg nitrogen source tested, ammonium chloride showed maximum biosurfactant production of 2.41 g/L.
The biosurfactant produced by the bacterial isolate reduced the sucface tension of the cell free broth from 53.56 mN/m to 29.48 mN/m. Compositional analysis of the biosurfactant revealed that it was of lipopetide type, composed of high percentage of lipid and protein content.