Hydrocarbonoclastic bacteria and the strategies for improving biodegradation

Abstract

Marine oil spills either by accidental spillage or intentional disposal oil are a serious concernto Goa tourism sector. The spilled oil turns into tarballs due to physical, biologicalweathering and gets transported to beaches by ocean currents. Tarballs were collected from newlinethe beaches and subjected to incineration resulting in air pollution. It was proved that newlinebioremediation is an ecofriendly technique involving hydrocarbon degrading bacteria. There newlineare different problems faced during bioremediation of marine oil spills. For instance newlinebioavailability of hydrocarbons was limited due to their hydrophobic nature, limitation of newlinenutrients questioning the survival of employed bacteria, limited knowledge about newlinehydrocarbon transport into the bacteria. newlineHydrocarbon degrading bacteria was isolated using diesel oil as sole carbon source from newlineVelsao beach, Goa. Denaturing gradient gel electrophoresis (DGGE) was performed for the newlineenriched culture and it was found that Pseudomonas aeruginosa (AEBBITS1) and newlineEscherichia fergusonii (AEBBITS2) were present. Microcosm study was performed for 45 newlinedays to analyze the capabilities of bacteria to degrade crude oil sediment (tarball from Velsao newlinebeach). Based on GC-MS results it was found that alkanes were degraded extensively (98% newlineto 66%) compared to Polyaromatic hydrocarbons (PAH). It was also found that the newlinedegradation of PAHs was decreased with increase in ring number and the alkylated PAHs newlinewere less degraded compared to unalkylated ones. DGGE was performed for the microcosm newlinesetup and it was evident from the result that both AEBBITS1 and AEBBITS2 have survived newlinetill last day of the experiment. newlineHydroxy cucurbit[6]uril (Hydroxy CB[6]) was a cyclic polymer with a hydrophobic inner newlinecavity. It was reported that cucurbiturils are potential hydrophobic drug delivery agents and newlinealso their host-guest interaction with hydrocarbons was reported. Degradation of aliphatic newlinehydrocarbons (Tetradecane, Hexadecane, Octadecane) in presence of Hydroxy cucurbit[6]uril newlinewas studied. Microcosms were setup usi