Abstract

Our previous studies showed that the biodegradation of petroleum oil by apseudomonas isolated from a petroleum-contaminated soil was instable. In this work, it is shown that when the isolates are immobilized on Perlite, they are more stable for oil degradation. Although the isolate did not have any chemotaxis to octadecane, dodecane and octane but utilize octadecane and dodecane better than octane and it did not utilized hexane, benzene, kerosene, pentane, heptane or thiophenol. The generation time for degradation of petroleum oil, dodecane and octadecane was 20, 22, and 25 h respectively. This phenotype was not transformed to Pseudomonas by conjugation even with lysozyme treatment, however the petroleum oil and octadecane utilization were transformed to E. coli by lysozyme treatment. The transformed E. coli lost the ability to use octadecane after three subcultures on nutrient broth and 34 generations.

Key words: Petroleum, transformation, chemotaxis, biodegradation, immobilization.