Catalyzes the third and final step of the '4S' desulfurization pathway that removes covalently bound sulfur from dibenzothiophene (DBT) without breaking carbon-carbon bonds. Oxidizes 2-(2'-hydroxyphenyl)benzene sulphinate (HBPS) to 2-hydroxybiphenyl (HBP) plus sulfite (PubMed:7961424, PubMed:7574582, PubMed:9634856, PubMed:9308179, PubMed:31545606). The rate-limiting step of the '4S' desulfurization pathway (PubMed:9308179, PubMed:31545606). The pathway substrate specificity has been augmented using mutagenesis, however no mutations allowed use of alkylated thiophenes (PubMed:11823208). 2'-hydroxybiphenyl-2-sulfinate + H2O = biphenyl-2-ol + H(+) + sulfite Inhibited by the end product HBP. kcat is 2 min(-1). Sulfur metabolism; dibenzothiophene degradation. Monomer. Expressed during growth on DBT or DMSO as sole sulfur source; this protein accumulates to lower levels than DszA or DszC (at protein level) (PubMed:8932295). Part of the probable dszA-dszB-dszC operon (Probable). Desulfurization is repressed by sulfate, cysteine and methionine (PubMed:7574582, PubMed:8932295). Has 2 domains; domain A (residues 1-97 and 252-365) and domain B (residues 98-251). The active site with bound substrates is found between them. Upon substrate binding His-60 moves into the active site. Blocks the desulfurization of DBT to 2-HBP, accumulates an unknown intermediate that is not DBTO2. Can be used to remove sulfur from polycyclic aromatic sulfur compounds found in gasoline and diesel (biodesulfurization), which are a considerable source of pollution. In addition it may be possible to engineer the operon to make specialty chemicals. Belongs to the DszB desulfinase family.