Biosurfactant from Paenibacillus dendritiformis and its application in assisting polycyclic aromatic hydrocarbon (PAH) and motor oil sludge removal from contaminated soil and sand media

A novel biosurfactant was produced by strain CN5, identified as Paenibacillus dendritiformis isolated from creosote contaminated wood treatment plant soil. The biosurfactant produced by the strain was identified as lipopeptidal after attenuated total reflectance Fourier transform infrared (ATR-FTIR), thin-layer chromatography (TLC), and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. The MS/MS analysis of the biosurfactant showed that it has an amino acid sequence of Cys-Gly-Ala-Gly-Ile-Asn-Leu and a long chain fatty acid of molecular mass 522 Da. The biosurfactant exhibited 74% and 82% emulsification index (E24) with hexane and cyclohexane respectively, and it showed high thermal, pH and saline stability over a wide range of temperature, pH and salinity. The ability of the biosurfactant to desorb PAH from spiked soils and motor oil from spiked sands was tested in batch experiments and it desorbed more than 96% of phenanthrene, 83% of pyrene from the contaminated soil in 5 days and 81% of heavy used motor oil sludge from the spiked sands in 24 h. This suggests the potential application of the biosurfactant for the removal of PAHs and motor oil sludge from contaminated media and enhancing their bioremediation by increasing bioavailability and possible application of the biosurfactant for enhanced oil recovery.