Carbazole biodegradation in gas oil/water biphasic media by a new isolated bacterium Burkholderia sp. strain IMP5GC

To select carbazole-degrading bacteria able to survive and metabolize carbazole in biphasic organic-water media and to study the factors affecting carbazole degradation in such conditions. In this research a new carbazole-degrading strain was isolated from hot springs in Mexico. This bacterium was preliminary identified as Burkholderia sp. IMP5GC and was able to grow using carbazole as sole carbon and nitrogen source. Genetic analysis showed that this bacterium carries carA genes identical to those reported in Pseudomonas resinovorans CA10. Burkholderia IMP5GC efficiently degraded carbazole in aqueous media as well as in biphasic media with n-hexadecane. Furthermore, the strain IMPGC5 efficiently reduced the concentration of carbazole and monomethyl carbazole species in gas oil-water biphasic media. This study demonstrates the biodegradation of carbazole in biphasic gas oil/water media (1 : 1), regardless of the highly toxic effects of this petroleum distillate. Biodegradation of carbazole in biphasic media contributes to the understanding and design of bioprocesses for carbazole removal from petroleum-upgrading fractions and other carbazole-rich organic mixtures.