Isolation and Characterisation of Polycyclic Aromatic Hydrocarbon Degrading Soil Microbes from Automobile Workshop Sediments

摘要

Polycyclic aromatic hydrocarbons are the most important components of contaminants retained in the soil environment after any oil spill age. Certain indigenous organisms are known to degrade these contaminants by using them as sole carbon source . The aim of the study was to screen Polycyclic Aromatic Hydrocarbon (PAH) Degrading Soil Microbes from an Automobile Workshop Sediments. Among the 34 oil-degrading microbial isolates collected from petrochemical contaminated workshop sediments of Puducherry in India five isolates are screened and selected based on their efficiency to mineralize Polycyclic Aromatic Hydrocarbons. The efficiency of biodegradation is assessed using soil dehydrogenase test to measure microbial activity when supplied with individual PAHs, in addition to different concentrations of phenanthrene. Studies with different concentrations of phenanthrene showed linear increase in growth with percentage increase of phenanthrene in case of ISO2 where 0.16±0.04 to 0.72±0.06 was the Optical Density (OD) whereas minimal OD was observed in ISO5 while in ISO1 and ISO3 phenanthrene utilization was variable. The bioaugmentation ability of isolated strains was quantified by monitoring PAH removal by HPLC. A degradation percentage of 86.08 (naphthalene), 81.87 (fluorene), 77.77 (acenaphthene), 78.5 (phenanthrene) and 72.56 (benzanthracene) is observed in ISO2. The capacity of isolated strains to mineralize 5 hydrocarbons is presented in this study wherein ISO2 showed a consistent degradation and higher metabolic versatility in comparison to other strains in all the experiments. All the results indicated that the identification of degradable strains have a promising application in understanding the role of microbes in bioremediation of petrochemical contaminated environments and these strains could be potentially useful for PAH bioremediation in the field.