Abstract: The oil-degrading bacteria X-1 (Bacillus sp.) with capability of generating biosurfactant was isolated from petroleum-contaminated soil. The biosurfactant produced by the bacteria X-1 was extracted and identified. And the optimal conditions on biosurfactant production were studied. The results showed that the biosurfactant from strain X-1 was light yellow powdery material. By silica gel TLC and FT-IR analysis, the biosurfactant was determined as lipopeptid and lipoproteins. The optimal conditions for biosurfactant production were 32 ℃, pH 7. 0 and 2 g/L NaCl. And the best carbon source and nitrogen source were starch and peptone, respectively.

Key words: oil-degrading bacteria, biosurfactant, TLC, FT-IR, ipopeptid, optimization