Citation:

Hammel, K., W. Gai, B. Green, AND M. Moen. OXIDATIVE DEGRADATION OF PHENANTHRENE BY THE LIGNINOLYTIC FUNGUS PHANEROCHAETE CHRYSOSPORIUM. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/192 (NTIS PB93199511), 1992.

Description:

The ligninolytic fungus Phanerochaete chrysosporium oxidized phenanthrene and phenanthrene-9,10-quinone (PQ) at their C-9 and C-10 positions to give a ring-fission product, 2,2'-diphenic acid (DPA), which was identified in chromatographic and isotope dilution experiments. PA formation from phenanthrene was somewhat greater in low nitrogen (ligninolytic) cultures than in high-nitrogen (nonligninolytic) cultures and did not occur in uninoculated cultures. he oxidation of PQ to DPA involved both fungal and abiotic mechanisms, was unaffected by the level of nitrogen added, and was significantly faster than the cleavage of phenanthrene to DPA. henanthrene-trans-9,10-dihydrodiol, which was previously shown to be the principal phenanthrene metabolite in nonligninolytic P. chrysosporium cultures, was not formed in the ligninolytic cultures employed here. hese results suggest that phenanthrene degradation by ligninolytic P. chrysosporium proceeds in order from phenanthrene -PQ - DPA, involves both ligninolytic and nonligninolytic enzymes, and is not initiated by a classical microsomal cytochrome P-450. he extracellular lignin peroxidases of P. chrysosporium were not able to oxidize phenanthrene in vitro and therefore are also unlikely to catalyze the first step of phenanthrene degradation in vivo. oth phenanthrene and PQ were mineralized to similar extents by the fungus, which supports the intermediacy of PQ in phenanthrene degradation, but both compounds were mineralized significantly less than the structurally related lignin peroxidase substrate pyrene was.

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