Detection of toluene degradation in isolated bacteria from oil contaminated soils

Abstract

Toluene (C7H8) afuel hydrocarbons, is a common contaminants of soil and groundwater. In this study the rate of bacterial growth and their ability for degrading toluene were determined in twelve bacteria. From the bacterial growth curves, Pseudomonas aeruginosa UKMP-I4T was shown to have the highest growth in toluene. The highest growth is observed during the third days of culturing. This bacterium was able to grow in 250 liM of toluene Beside Pseudomonas aeruginosa UKMP-I4T, Bacillus cereus UKMP- 6G was also able to grow in 250 jiM toluene. Both Pseudomonas aeruginosa UKMP-14T and Bacillus cereus UKMP-6G were shown to have the ability to degrade toluene by looking at the related enzymes activity. The activity of toluene degradation was analysed by using two methods, Horseradish peroxidase (HRP) and indole -indigo .Both of the methods monitor the production of catechol which was synthesized by the enzymatic reaction of toluene monooxygenase . In the HRP based assay, the enzyme activities were 0.274 Ulml and 0.260 Ulml in Pseudomonas aeruginosa UKMP-14T and Bacillus cereus UKMP-6G respectively. However, the enzyme activities were slightly different in 1ndole-indigo assay. In the assay, the rates of enzyme activities were 0.204 U/ml and 0.291 U/ml for Pseudomonas aeruginosa UKMP-14T and Bacillus cereus UKMP-6G respectively. Based on both of the experiments, it was shown that Pseudomonas aeruginosa UKMP-14T and Bacillus cereus UKMP-6G were able to degrade toluene.