Five substances, water soluble organic sulfur compounds, produced from dibenzothiophene by such bacteria as Pseudomonas jianii or Ps. abikonensis were isolated from culture broth. Three products of them were identified as 3-hydroxy-2-formyl-benzothiophene, di-benzothiophene-5-oxide and 3-oxo-2 [3'-hydroxy-thionaphthenyl-(2)-methylene]dihydrothiona-phthene respectively.