Identification of the gene encoding a NAD(P)H-flavin oxidoreductase coupling with dibenzothiophene (DBT)-desulfurizing enzymes from the DBT-nondesulfurizing bacterium Paenibacillus polymyxa A-1

The gene encoding NAD(P)H-flavin oxidoreductase (flavin reductase), which c ouples efficiently with dibenzothiophene (DBT)-desulfurizing monooxygenases of Rhodococci, was cloned from a DBT-non-desulfurizing bacterium Paenibaci llus polymyxa A-1 in Escherichia coil, and designated as pv. Cell-free extr acts from the recombinant exhibited a flavin reductase activity about forty times higher than that of the E. coli carrying the vector DNA only. Nucleo tide sequence analysis reveals that the gene product consists of 208 amino acids and showed about 27%, 32% and 21% identity in amino acid sequence wit h FRase I, the major flavin reductase of Vibrio fischeri, the NADH dehydrog enase of Thermus thermophilus and several members of the nitroreductase fam ily, respectively. The coexpression of flv with two kinds of desulfurizing genes, dszABC and tdsABC, in E. coil enhanced the rate of DBT degradation b y about 10 and 5 times as high as in the case without pv, respectively.