Isolation of a recombinant desulfurizing 4,6-diproply dibenzothiophene in n-tetradecane.

Rhodococcus erythropolis strain KA2-5-1 is unable to desulfurize 4,6-dipropyl dibenzothiophene (DBT) in the oil phase. The dsz desulfurization gene cluster from R. erythropolis strain KA2-5-1 was transferred into 22 rhodococcal and mycobacterial strains using a transposon-transposase complex. The recombinant strain MR65, from Mycobacterium sp. NCIMB10403, was able to grow on a minimal medium supplemented with 1.0 mM 4,6-dipropyl DBT in n-tetradecane (50%, v v ) as the sole sulfur source. Resting cells of recombinant strain MR65 could desulfurize 68 mg l- of sulfur in light gas oil (LGO) containing 126 mg sulfur l-. Strain MR65 had about 1.5-times the LGO desulfurization activity of R. erythropolis strain KA2-5-1. The application of a recombinant, which is able to utilize 4,6-dipropyl DBT in the oil phase, was effective in enhancing LGO biodesulfurization.