Specific desulfurization of dibenzothiophene by Mycobacterium sp. strain G3

Various microorganisms were screened for their ability to desulfurize dibenzothiophene (DBT) via a sulfur-specific pathway. Based on the desulfurization activity, strain G3 was selected as the best strain. From taxonomical studies, the strain was shown to belong to the genus Mycobacterium. Dibenzothiophene was degraded by both growing and resting cells of this strain, and 2-hydroxybiphenyl was detected as a dead-end product. Strain G3 could also desulfurize 4,6-dimethylDBT. Sulfate ion repressed the expression of the DBT desulfurizing enzyme(s). Accumulation of 2-hydroxybiphenyl produced severe inhibitory effects on both cell growth and DBT desulfurization. Resting cells of this strain could desulfurize about 250 ppm of DBT or 4,6-dimethylDBT within 12h.