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Abstract

1-Hydroxy-2-naphthoate is formed as an intermediate in the bacterial degradation of phenanthrene. A monooxygenase which catalyzed the oxidation of 1-hydroxy-2-naphthoate to 1,2-dihydroxynaphthalene was purified from the phenanthrene- and naphthalene-degrading Pseudomonas putida strain BS202-P1. The purified protein had a molecular weight of 45 kDa and required NAD(P)H and FAD as cofactors. The purified enzyme also catalysed the oxidation of salicylate and various substituted salicylates. The comparison of the Km and Vmax values for 1-hydroxy-2-naphthoate and salicylate demonstrated a higher catalytic efficiency of the enzyme for salicylate as a substrate. A significant substrate-inhibition was detected with higher concentrations of 1-hydroxy-2-naphthoate. The aminoterminal amino acid sequence of the purified enzyme showed significant homologies to salicylate 1-monooxygenases from other Gram negative bacteria. It was therefore concluded that during the degradation of phenanthrene the conversion of 1-hydroxy-2-naphthoate to 1,2-dihydroxynaphthalene is catalysed by a salicylate 1-monooxygenase. Together with previous studies, this suggested that the enzymes of the naphthalene pathway are sufficient to catalyse also the mineralization of phenanthrene.

Biodegradation Ability and Catabolic Genes of Petroleum-DegradingSphingomonas koreensisStrain ASU-06 Isolated from Egyptian Oily Soil

“…Phenanthrene-4,5-dicarboxylic then converted to 1-hydroxy-2-naphthoic acid. Two common metabolic pathways for 1-hydroxy-2-naphthoic acid are (a) formation of 2-carboxy benzal pyruvate under the catalysis of 1-hydroxy-2-naphthoate dioxygenase [43] and (b) dihydroxynaphthalene under the catalysis of salicylate-1-hydroxylase [44]. In the present study, 2-carboxy benzal pyruvate was found but there were no traces of dihydroxynaphthalene.…”

Mycobacterium aromativorans JS19b1T degrades phenanthrene through C-1,2, C-3,4 and C-9,10 dioxygenation pathways

“…Although the degradation rate was slow, diphenic acid (P11) can be metabolized to biphenyl-2-carboxylic acid (P14). Decarboxylation of hydroxyaryl carboxylic acid by bacteria is usually accompanied by hydroxylation to produce dihydroxyaryl compound (Balashova et al , 2001). However, 1-hydroxynaphthalene was reported as a phenanthrene metabolite, which suggests the presence of decarboxylation without hydroxylation (Kim et al , 2005).…”

“…Two common metabolic pathways for 1-hydroxy-2-naphthoic acid are (a) formation of 2-carboxybenzalpyruvate under the catalysis of 1-hydroxy-2-naphthoate dioxygenase (Adachi et al , 1999) and (b) DHN (P15) under the catalysis of salicylate-1-hydroxylase (Balashova et al , 2001). In the present study, DHN was found, but no trace of 2-carboxybenzalpyruvate.…”

“…The initial reactions of PAHs degradation are often catalyzed by multi-component dioxygenases to produce dihydrodiols (Moody et al , 2003 and 2004; Kim et al , 2005; Mallick et al , 2007). In addition to the formation of cis -dihydrodiol, PAH dioxygenase from Pseudomonas species catalyzes several different reactions, including desaturation and monooxygenation (Gibson et al , 1995; Balashova et al , 2001). Mycobacterium species usually incorporate mono- or di-oxygens at several different sites of specific PAHs (Moody et al , 2001 and 2003; Kim et al , 2007).…”

“…To our knowledge, diphenic acid breakdown has not well been described in the literature. 1-Hydroxy-2-naphthoic acid is metabolized either to 1,2-dihydroxynaphthalene (Balashova et al , 2001) or 2-carboxybenzalpyruate (Adachi et al , 1999). Although both salicylic acid and phthalic acid could be produced from phenanthrene, the latter is more commonly found as the final metabolite in Mycobacterium species than the former (Moody et al , 2001; Kim et al , 2005).…”