Isolation and characterization of fatty acid esters and phosphatidylethanolamine surfactants from a consortium of marine bacteria

Abstract

Consortium of five bacterial isolates from marine environment produced extracellular surface-active metabolites during growth in culture medium containing High Speed Diesel (HSD) as the sole source of carbon and energy. Product obtained was characterized for its surface-active properties and chemical constituents. It was found to reduce the surface tension of distilled water from 72 to 36 mN/m. Fourier Transform Infra Red (FTIR) spectrum revealed the presence of functional groups such as alkyl, ester, carboxyl, amine and alcohol indicating its structural similarity to mixture of fatty acid esters and amino group containing lipids. Major constituent was lipids (74.49%) which on further analysis by Thin Layer Chromatography (TLC) and Gas Chromatography – Mass Spectroscopy (GCMS) showed the presence of amino group containing phospholipids and different fatty acids. Thermogravimetric analysis indicated the material to be thermostable (Initial Decomposition Temperature: IDT = 198^oC). Characterization therefore indicated the reported biosurfactant to be a mixture of hydrophobic and hydrophilic moieties facilitating the amphiphilic behaviour useful for the effective emulsification and dispersion of petroleum hydrocarbons.