Degradation of 2,4,5-trichlorophenol by the lignin-degrading basidiomycete Phanerochaete chrysosporium
Degradation of 2,4,5-trichlorophenol by the lignin-degrading basidiomycete Phanerochaete chrysosporium
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DOI：
10.1128/aem.59.6.1779-1785.1993
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发表时间：
1993-06
影响因子：
4.4
通讯作者：
D. K. Joshi;M. H. Gold
中科院分区：
文献类型：
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作者：
D. K. Joshi;M. H. Gold
在次生代谢条件下，白腐担子菌黄孢Phanerochaete chrysosporium迅速矿化2,4,5-三氯苯酚。通过对纯化木质素过氧化物酶（LiP）和锰过氧化物酶（MnP）的真菌代谢产物和氧化产物的表征，阐明了2,4,5-三氯苯酚的降解途径。该多步骤途径包括过氧化物酶催化的氧化脱氯反应循环，然后是醌还原反应，生成关键中间体1,2,4,5-四羟基苯，该中间体可能是环裂的。在该途径的第一步，2,4,5-三氯苯酚被MnP或Lip氧化为2,5-二氯-1,4-苯醌，然后2,5-二氯-1,4-苯醌被还原为2,5-二氯-1,4-对苯二酚。2,5-二氯-1,4-对苯二酚被MnP氧化生成5-氯-4-羟基-1,2-苯醌。正醌又被还原成5-氯-1,2,4-三羟基苯。最后，5-氯三羟基苯经过另一轮氧化脱氯和还原反应生成1,2,4,5-四羟基苯。后者可能是环裂的，随后降解为二氧化碳。在这个途径中，底物被LiP或MnP氧化脱氯，产生醌。醌中间体通过还原反应再循环生成中间体作为过氧化物酶催化氧化脱氯的底物。这一途径显然导致在环裂解发生之前所有三个氯原子都被去除。
Under secondary metabolic conditions the white rot basidiomycete Phanerochaete chrysosporium rapidly mineralizes 2,4,5-trichlorophenol. The pathway for degradation of 2,4,5-trichlorophenol was elucidated by the characterization of fungal metabolites and oxidation products generated by purified lignin peroxidase (LiP) and manganese peroxidase (MnP). The multistep pathway involves cycles of peroxidase-catalyzed oxidative dechlorination reactions followed by quinone reduction reactions to yield the key intermediate 1,2,4,5-tetrahydroxybenzene, which is presumably ring cleaved. In the first step of the pathway, 2,4,5-trichlorophenol is oxidized to 2,5-dichloro-1,4-benzoquinone by either MnP or Lip. 2,5-Dichloro-1,4-benzoquinone is then reduced to 2,5-dichloro-1,4-hydroquinone. The 2,5-dichloro-1,4-hydroquinone is oxidized by MnP to generate 5-chloro-4-hydroxy-1,2-benzoquinone. The orthoquinone is in turn reduced to 5-chloro-1,2,4-trihydroxybenzene. Finally, the 5-chlorotrihydroxybenzene undergoes another cycle of oxidative dechlorination and reduction reactions to generate 1,2,4,5-tetrahydroxybenzene. The latter is presumably ring cleaved, with subsequent degradation to CO2. In this pathway, the substrate is oxidatively dechlorinated by LiP or MnP in a reaction which produces a quinone. The quinone intermediate is recycled by a reduction reaction to regenerate an intermediate which is again a substrate for peroxidase-catalyzed oxidative dechlorination. This pathway apparently results in the removal of all three chlorine atoms before ring cleavage occurs.