Production and characterization of biosurfactant by marine bacterium Pseudomonas stutzeri (SSASM1)

Biosurfactant-producing bacteria were isolated from sediment sample collected from Pondicherry harbour region, south-east coast of India. Isolates were screened for the biosurfactant production using crude oil as substrate. The selected strain was identified by 16S rDNA gene sequencing analysis and was tentatively identified as Pseudomonas stutzeri (SSASM1) strain. Additionally, the emulsification activity was carried out and found 77.6%. The surface tension reduction test showed 33.5 mN/m. The biosurfactant produced was characterized using rhamnose test, Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance (H-1 NMR) and found as rhamnolipid nature. The H-1 NMR spectra of the biosurfactant displayed a number of signals confirming the presence of different sugar moieties and aromatic groups and also showed the occurrence of long aliphatic hydrocarbon chain-(CH2). The (HNMR)-H-1 graph emphasized the biosurfactant, showing the resonance signals between 0.792 and 1.845 ppm.