BIOREMEDIATION OF OIL SPILL IN WATER

Abstract

In all countries, oil exploration and use threatens the health of the environment and living creatures including humans. An oil spill is the release of petroleum hydrocarbon into the environment. One of the most applicable and safe method is the bioremediation treatment, using microorganisms. This work aims at treating oil spills in fresh water and sea water to compile information on types and properties of biosurfactant. It also describes factors affecting these biosufactants production. Different screening methods e.g. oil spreading assay, Emulsification index (E24), Drop collapse assay, Blood agar test, Hemolysis, MaCconkey agar test were tested. Three isolates gave high Emulsification tests named O3, O11, H2 which were identified as Bacillus subtilis, Bacillus licheniformis, and Bacillus licheniformis (isolated from sea water) respectively, were isolated from petroleum hydrocarbon contaminated fresh and sea water. Optimization of three isolates were done and highest biosurfactant activity at temperature ranges from 10 oC to 50 oC and pH ranges from 3 to 10 and salinity ranges from 0%to 30%. Also, the biosurfactant was characterized by Fourier transform infrared spectroscopy (FTIR) and surface tension measurement. FTIR showed the production of biosurfactant from Bacillus subtilis similar to surfactin, while the biosurfactant from two isolates Bacillus licheniformis (one from fresh oil contaminated water and the other from contaminated sea water with oil spill) similar to lichenysins. The use of microbial biosurfactants significantly decreases the hydrophobicity and increases the rate of hydrocarbon biodegradation. Biosurfactants obtain demonstrated good surface tension reduction capacity by Bacillus subtilis and Bacillus licheniformis, and Bacillus licheniformis (isolated from sea water) up to 30,36,and 35 Nm/m and have emulsifying activity 71%, 65% and 62% respectively. Keywords: Bioremediation-Biosurfactant-Oilspill-Surface tens