SUPEROXIDE DISMUTASE ACTIVITY IN AZOTOBACTER VINELANDII IN THE DISPOSITION OF ENVIRONMENTAL TOXICANTS EXEMPLIFIED BY FENTON REAGENT AND CRUDE OIL

Abstract

The role of superoxide dismutase (SOD) in the survival of diazotrophic bacteria exemplified by Azotobacter vinelandii in the disposition of crude oil-contaminated environment was investigated. The extent of survival, ranging between 57-64% relative to control, was based on colony-forming units of Azotobacter inocula taken from media contaminated with crude oil (0.5-1.5%, w/v), after plating on nutrient agar. The specific activity of superoxide dismutase in the crude protein extracts from cells harvested from oil-contaminated medium and Fenton reagent-containing mediumin creased by 1.25 and 1.28-fold,respectively, relative to control. These results suggest an induction in SOD enzyme protein as a defense mechanism to protect the exposed bacterial cells from the free radicals/reactive oxygen species generated during the oxidation (co-metabolism) of the petroleum hydrocarbons.