ISOLATION AND IDENTIFICATION OF PETROL DEGRADING MICROORGANISMS FROM CONTAMINATED SOIL AND COMPARISON OF THEIR BIOREMEDIATION POTENTIAL

Abstract

The present work was aimed to isolate bacterial strains capable of metabolizing engine oil in the studied environments which can later be used in biotechnology for environment de-pollution. Petrol contaminated soil samples were collected from eighteen filling stations at Dehradun, Uttarakhand, India. Nine strains were isolated from various petroleum contaminated sites using enrichment technique. All the isolated strains were identified by staining and biochemical tests. They included Enterobacter sp., Klebsiella sp., Enterococcus sp., Streptococcus sp., and Serratia sp. Biosurfactant activity of the isolated strains was detected using drop collapsing test, oil spreading method and emulsification stability test. Enterococcus sp. produced maximum biosurfactant activity followed by Serratia sp. and Klebsiella sp. while Enterobacter sp. produced 61.11% emulsification index followed by 50.00% by Klebsiella sp. and 47.36% by Serratia sp. The percentage of petroleum hydrocarbon degradation was determined by gravimetric assay at 7 days interval for a total period of 35 days. Streptococcus sp. degraded 95.45% of oil in 35 days followed by 90.09% of oil by Enterobacter and Klebsiella sp. and 81.81% by Enterococcus sp.