Biosurfactant production by Serratia rubidaea SNAU02 isolated from hydrocarbon contaminated soil and its physico-chemical characterization

The aim of the study was to characterize and optimize the growth media for biosurfactant production from Serratia rubidaea SNAU02 isolated from hydrocarbon-contaminated soil from Cuddalore district, Tamilnadu, India. The biosurfactant produced by S. rubidaea SNAU02, was able to reduce the surface tension to 34.4 mN m−1 in MSM medium. The biosurfactant was characterized by FT-IR and GC–MS analysis. The GC–MS analysis shows that dirhamnolipid was detected in abundance as predominant congener than monorhamnolipid. The response surface methodology (RSM) -central composite design (CCD) was performed to optimize the media for biosurfactant production. The maximum emulsification index was obtained under the optimal condition of 29.31 g L−1 mannitol; 2.06 g L−1 yeast extract, medium pH 6.97 and 5.69 g L−1 NaCl. The biosurfactant produced by S. rubidaea recovered 92% of used engine oil adsorbed to a sand sample, suggested the potential application in microbial enhanced oil recovery and bioremediation.