Bacterial Degradation of Crude Oil by Gravimetric Analysis

Microbial degradation of petroleum hydrocarbons is one of the major practices in natural decontamination process. The present study investigated about the isolation of bacteria from crude oil contaminated site and gravimetric analysis of degradation in which, two bacterial isolates formed maximum clearing zone on mineral salt medium. Among these isolate S2 showed maximum growth (0.85mg/ml) and degradation on seventh day of incubation, followed by S10 that showed maximum growth (0.92mg/ml) and degradation. Isolate S2 was identified as Bacillus subtilis and S10 as Pseudomonas aeruginosa, were optimum for both growth and degradation. The total viable count of Bacillus subtilis and Pseudomonas aeruginosa were 257x10 Cfu and 248x10 Cfu respectively. An increase in oil degradation was correlated to an increase in cell number indicating that the bacterial isolates were responsible for the oil degradation. Our results obtained demonstrate the potential for biodegradation of these isolates in situ and/or ex situ. Key word: Decontamination, biodegradation, Bacillus subtilis, Pseudomonas aeruginosa, gravimetry. _____________________________________________________________________________________________