Isolation of biosurfactant-producing marine bacteria

Abstract

Biosurfactant-producing marine bacteria were isolated from oil-spilled seawater collected from harbors and docks in Mumbai, India. Haemolytic activity, emulsification activity toward n-hexadecane, emulsion of mixtures of oils, drop collapsing test as well as oil displacement test were used to determine biosurfactant producing activity of marine bacteria. Among 25 strains, 20 different strains showed biosurfactant activity in which only 6 strains had haemolytic activity and were able to emulsify mixtures of oils (kerosene + petrol + diesel) in Marine Broth 2216 during cultivation. Six strains named MW1, JN1, MS3, JN2, MS1, and MW2 were identified by various identification tests. MW2 (Pseudomonas sp.) Strain showed the highest emulsification activity against n-hexadecane. In addition, MW2 showed the highest activity for oil  displacement test (3.14 ± 0.02) and emulsification test (70.5 ± 0.55) towards nhexadecane.

Key words: Biosurfactant, emulsification, bacteria, haemolytic, extreme conditions, oil.