Enhanced biodesulfurization by expression of dibenzothiophene uptake genes in Rhodococcus erythropolis

The transfer of dibenzothiophene (DBT) and its derivatives into cells is a critical step for biodesulfuriza- tion. The desulfurization reactions of resting cells and cell lysate were studied, which showed that the desulfurization rate of DBT, especially 4, 6-dimethyldibenzothiophene (4, 6-DMDBT) in Rhodococcus erythropolis LSSE8-1 was seriously affected by the transfer into cells. The inhibited effect of NaN3 on desulfurization reactions was studied, which confirmed that the transfer of DBT into cells was an active transport in R. erythropolis LSSE8-1. The uptake- genes of DBT and its derivatives (HcuABC) of Pseudo- monas delafieldii R-8 were introduced into the specific desulfurization bacterium, R. erythropolis LSSE8-1. Compared with the wild type, the strains bearing HcuABC genes showed a higher desulfurization activity. The desulfurization ratio of DBT showed a 19% increase, and 13% increase of 4, 6-DMDBT.