Enhanced petroleum removal with a novel biosurfactant producer consortium isolated from drilling cuttings of offshore Akçakoca-5 in the Black Sea

Staphylococcus capitis, Achromobacter marplatensis (dominant strain), Enterobacter cloacae, Ochrobactrum anthropi, Bacillus velezensis, and Bacillus subtilis strains were isolated from drilling cutting samples. The potent biosurfactant-producing strains: S. capitis (A) & A. marplatensis (B) and non-biosurfactant-producing strains: E. cloacae (C) & O. anthropi (G) strains were combined (1:1) as AB, AC, AG, BC, BG, CG. The degradation efficiency of consortium AB was 90%, while that of consortia AC, BG and CG were 85%. Biosurfactant-producing strains belong to potent consortium AB facilitate petroleum uptake and biodegradation by increasing the solubility and surface area of substrate through emulsification activity. The physiological conditions of petroleum removal (92.5%) by potent consortium AB were optimized as: 1 g/L yeast extract, 1% petroleum, 3% NaCl at pH:7.0, 30 degrees C, 150 rpm for 7 days. GC/MS analysis revealed that the consortium AB not only degraded the short and medium-chain n-alkane fractions, but also removed the long-chain n-alkanes. The biosurfactant produced (0.5 g/L) by potent consortium AB was purified by silica gel 60 chromatography, further characterized by its lipopeptide structure with TLC, FT-IR, and SEM analyses. A new halotolerant consortium AB will make a significant contribution to MEOR applications in marine ecosystem.