Pseudomonas putida IFO13696, a recombinant strain with dsz desulfurization genes, desulfurized dibenzothiophene (DBT) in water but not in n-tetradecane. By introducing into this recombinant strain the hcuABC genes that take part in the uptake of DBT in the oil phase into the cell, 82% of 1 mM DBT in n-tetradecane was degraded in 24 h by resting cells. The products of hcuABC genes thus acted in the uptake of DBT in n-tetradecane into the cells and were effective in desulfurization of DBT in the hydrocarbon phase.