ISOLATION OF A SOIL BACTERIAL STRAIN CAPABLE OF DIBENZOTHIOPHENE DEGRADATION

摘要

Biocatalytic degradation of organo-sulphur aromatic heterocycles is still not a commercial technology. However, exploitation of this biological process through molecular engineering as well as analysis of biotransformation rates have revealed that this approach is very promising for environmental applications. Dibenzothiophene (DBT) has been selected as a model for the chemical architecture of the organic sulphur in the fossil fuel matrices. A bacterium belonging to Burkholderia sp., capable of oxidising DBT, has been isolated from toxic sediments contaminated by oil refinery wastewater. The corresponding genetic elements responsible for DBT oxidation has been cloned. The cloned genetic determinants can be classified as a new group of catabolic genes dealing with biodegradation of polycyclic aromatic sulphur-containing heterocycles (PASHs). They are organised in two separate transcriptional units. To the best of our knowledge the data reported here are the first showing a divergent organisation of genes involved in DBT oxidation, and they represent a step forward to understand the prevalence and distribution of the different groups of PASHs catabolic genes that occur in a contaminated soil.