深海细菌Celeribacter indicus P73T对菲的降解机制

The phenanthrene degradation mechanism of deep sea bacterium Celeribacter indicus P73T

来自深海环境的多环芳烃降解菌Celeribacter indicus P73T能够高效降解菲,为揭示菲生物降解的分子机制,对其降解途径进行分析.通过GC-MS联用技术鉴定出菌株P73T降解菲的2个重要的中间代谢产物,1-羟基-2-萘甲酸和1-萘酚.通过分析菌株P73T全基因组,发现了菲降解基因簇（P73 0346-P730354）,编码包括环羟基化双加氧酶、二氢二醇脱氢酶、环裂解双加氧酶、异构酶、水合醛缩酶等.通过验证环羟基化双加氧酶大亚基基因突变株ΔP73_0346：：kan的菲降解能力,证实基因P73 0346编码了菲双加氧酶.依据代谢物检测、基因组分析和突变株功能验证结果,推测菌株P73T降解菲经由菲C3,4-双加氧途径,更进一步地确定了参与此途径的菲双加氧酶等降解相关基因.本研究不仅揭示了菲降解的分子机制,也为菲污染的生物修复技术提供了理论依据.

Phenanthrene, a low-molecular-weight polycyclic aromatic hydrocarbon （PAH） comprising three aromatic rings, has been used as a model compound for biodegradation studies. Deep-sea PAH-degrader Celeribacter indicus P73 T, effective in degrading phenanthrene, was subjected to biodegradation mechanism analysis. Metabolites detection by GC-MS revealed two important metabolites, 1-hydroxy-2-naphthoate and 1-naphthol, generated during phenanthrene degradation. Genomic analysis revealed that a gene cluster involved in phenanthrene degradation contained ring-hydroxylating dioxygenase, ferredoxin reductase, ferredoxin, 2,3-dihydroxy-2,3-dihydrophenylpropionate dehydrogenase, ring-cleaving dioxygenase, dehydrogenase PhnF, trans-o-hydroxybenzylidenepyruvate hydratase-aldolase, 2-hydroxychromene-2-carboxylate isomerase and catechol 2,3-dioxygenase. The mutant AP73_0346：：kan with a ring-hydroxylating dioxygenase （P73_ 0346） disrupted was disabled for phenanthrene degradation, indicating the dioxygenase encoded by gene P73_0346 is responsible for phenanthrene dioxygenation. Based on the metabolic data and the genomic analysis, here we proposed a pathway involved C3,4-dioxygenation for phenanthrene degradation by strain P73T, and the degradation genes involved in the pathway. This study expands our understanding of the molecular mechanism of phenanthrene degradation, which can be useful for the bioremediation applications.