Thermophilic biodesulfurization of dibenzothiophene and its derivatives by Mycobacterium phlei WU-F1

Dibenzothiophene (DBT) derivatives can be detected in diesel oil following hydrodesulfurization treatment, and they are widely recognized as target compounds for more efficient desulfurization. The moderately thermophilic bacterium Mycobacterium phlei WU-F1 was isolated for its ability to grow at 50°C in a medium with DBT as the sole source of sulfur. At 50°C, resting cells of WU-F1 degraded 0.81 mM DBT within only 90 min to produce 2-hydroxybiphenyl as a desulfurized metabolite through the selective cleavage of carbon-sulfur bonds, and also degraded 0.81 mM of derivatives such as 2,8-dimethylDBT, 4,6-dimethylDBT and 3,4-benzoDBT within 8 h. In addition, the resting cells exhibited high DBT-desulfurizing ability over a wide temperature range from 20 to 50°C. Because M. phlei WU-F1 possesses higher desulfurizing ability toward DBT and the derivatives over a wider temperature range than any other microorganisms previously reported, it may have useful practical applications for biodesulfurization.