Production and characterization of biosurfactant from Halomonas sp. BRI3

In this report, the halotolerant bacterium Halomonas sp. BRI3 was studied for its biosurfactant (BS) producing ability. Effect of carbon source, nitrogen source, temperature, inoculum concentration and incubation on the production of BS was studied and maximum production (14 g/L) was obtained in modified medium containing 1% glucose, yeast extract and ammonium chloride (0.25% each) with 5% inoculum concentration at 30°C after 48 h, which was 2.8 fold higher as compared to original medium (5 g/L). Highest emulsification index (72%) of crude BS was obtained with kerosene followed by n-hexane > crude oil > n-heptane > soybean oil > hexadecane > mustard oil > olive oil > sesame oil. Our hydrocarbon degradation experiments using crude oil and soybean oil revealed 40% decrease in crude oil and 60% decrease in soybean oil concentration after 50 days in presence of glucose, whereas, it was 20% and 50% in the absence of glucose, respectively. Based on TLC and FTIR analysis, the BS is chemically a glycolipo protein, demonstrated an significant antimicrobial and antiadhesive activity. We observed significant stability of BS over wide range of temperature (40 to 120°C) and pH (5.0 to 11.0), suggesting its potential for application in food, pharmaceutical and cosmetics industries