Enzymatic desulfurization of dibenzothiophene by a cell-free system ofRhodococcus erythropolisD-1

The enzymatic desulfurization of dibenzothiophene (DBT) to 2-hydroxybiphenyl (2-HBP) was detected in extracts of Rhodococcus erythropolis D-1 grown on DBT as a sole source of sulfur. In the dialyzed cell-free extracts, NADH was absolutely required for the activity. DBT desulfurization proceeded linearly with the reaction time, and stoichiometric amounts of 2-HBP were finally formed. The activity was stimulated by increasing the protein and NADH concentrations up to 5 mg ml−1 and 5 mM, respectively, when 0.1 mM DBT was present in the reaction mixture.