Abstract

SCREENING AND ISOLATION OF BIOSURFACTANT PRODUCING ORGANISM FROM OIL CONTAMINATED SOIL

Chandana Vineela K.*, Hemalatha V., Kalyani P., Sunanda Kumari K., Hemalatha K.P.J.

ABSTRACT

Biosurfactant is a structurally diverse group of surface-active molecule, synthesized by microorganisms. They are capable of reducing surface and interfacial tension with low toxicity, high specificity and biodegradability. The samples were enriched in nutrient agar containing diesel oil, serially diluted and poured on nutrient agar plate. Biosurfactant producing organisms were screened by using oil spreading method, Blood hemolysis test, Emulsification index (E24) and Drop collapse method. Out of 50 isolates, eleven strains showed positive biosurfactant production. Another interesting finding in this study was the use of crude oil as hydrophobic substrate for the isolation of biosurfactant producing bacterial strains; this approach may be useful during the initial isolation of biosurfactant producing bacteria to reduce the number of strains to be screened. These strains were characterized by using different biochemical tests like Gram’s staining, IMVIC etc., these strains were optimized for maximum biosurfactant production. Bacillus tequilensis showed 78% emulsification index and reduce the surface tension to 29mN/m. It is Gram positive, rod shaped and spore forming bacteria.

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