Hydroxylation of biphenyl by the yeast Trichosporon mucoides.
Hydroxylation of biphenyl by the dibenzofuran-degrading yeast Trichosporon mucoides SBUG 801 was studied. Glucose-grown cells degraded 40% of the biphenyl added within the first 24 h of incubation. The first step in the biotransformation pathway was the monohydroxylation of the biaryl compound to produce 2-, 3-, and 4-hydroxybiphenyl. Further oxidation produced seven dihydroxylated intermediates; the second hydroxyl group was added either on the aromatic ring already hydroxylated or on the second ring. Of all metabolites, 2,5-dihydroxybiphenyl accumulated in the supernatant in the highest concentration. The initial hydroxylation favors the 4-position to produce 4-hydroxybiphenyl, which is subsequently hydroxylated to form 3,4-dihydroxybiphenyl. When biphenyl was replaced as a substrate by 4-hydroxybiphenyl, further hydroxylation of the intermediate 3,4-dihydroxybiphenyl resulted in 3,4,4'-trihydroxybiphenyl. Incubation of T. mucoides with biphenyl and 18O2 indicated a monooxygenase-catalyzed reaction in the oxidation of biphenyl. The hydroxylation was inhibited by 1-aminobenzotriazole and metyrapone, known cytochrome P450 inhibitors. These results are very similar to those observed in the biotransformation of biphenyl in mammals.
Sietmann
R
R
Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität, Greifswald, Germany. sietmann@microbio1.biologie.uni-greifswald.de
Hammer
E
E
Moody
J
J
Cerniglia
C E
CE
Schauer
F
F
D001713:Biphenyl Compounds / Q000378:metabolism*; D003470:Culture Media; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006900:Hydroxylation; D009682:Magnetic Resonance Spectroscopy; D014250:Trichosporon / Q000254:growth & development / Q000378:metabolism*
D001713:Biphenyl Compounds; D003470:Culture Media; C010574:biphenyl