Studies on biosurfactant from Oceanobacillus sp BRI 10 isolated from Antarctic sea water

The search for new biosurfactant producing strains from uncommon or extreme microbial habitats has become increasingly important due to their biotechnological and environmental significance. In view of this, fourteen bacterial strains were isolated from eight different sea water samples obtained from various locations of Antarctica. All of them were screened for biosurfactant production and only the isolate BRI 10 was found to be positive in all the tests. It was identified as Oceanobacillus sp. BRI 10 based on 16S rRNA sequencing and phylogenetic analysis. The production of biosurfactant was found to be maximum (E24 = 55%) in the medium containing glucose (3%) and ammonium chloride (0.48%) at 30 degrees C, pH 8.0 at the end of 48 h. The biosurfactant was stable at higher temperature and at alkaline pH. TLC and FTIR analysis revealed that biosurfactant is a glycolipoprotein. It exhibited antimicrobial activity against Escherichia coli and no cytotoxicity against normal cell line. It is found to emulsify lubricant oil, crude oil, diesel and kerosene in the order kerosene > lubricant oil > diesel > crude oil. The emulsification activity (D-610) of biosurfactant was 0.64 as compared to 0.31 with SDS. Crude oil biodegradation experiments resulted in 56 and 90% degradation on 9th and 27th day respectively. These results suggested its applicability against diverse hydrocarbon pollution. (C) 2013 Elsevier B.V. All rights reserved.