Effect of Curing of Anoxybacillus rupiensis Strain Ir3 (JQ912241) Plasmid (s) in their Ability for Biodegradation of Carbazole

Aims: To study the effect of curing agents on A. rupiensis Ir3 (JQ912241) plasmid(s) and the plasmid(s) role in utilization of carbazole in this bacterium.

Study Design: Experimental study.

Place and Duration of Study: Department of Biotechnology, College of Science, Al-Nahrain University. Baghdad, Iraq, between October 2012 and February 2013.

Methodology: Anoxybacillus rupiensis strain Ir3 (JQ912241) a newly thermophilic bacterium capable to utilize aromatic hydrocarbons, was used. Plasmid profile of this bacterium was determined. This bacterium was treated with two curing agent’s in order to cure their plasmids.

Results: Plasmid profile of A. rupiensis strain Ir3 (JQ912241) showed that this bacterium contains large and small plasmid DNA bands. In order to determine the role of plasmid in utilization carbazole, many attempts were made to cure plasmid (s) of this bacterium using Sodium Dodecyl Sulfate (SDS) and Ethidium Bromide (Et.Br). Results indicated that no cured colonies (lost their ability to utilize carbazole at 70°C) were obtained. Plasmid isolated from some of these colonies being treated with Et.Br, indicated that these colonies are still harboring the large plasmid.

Conclusion: It was difficult to cure the large plasmid, and the utilization trait might be located on it or on the chromosome.