Open AccessA novel degradative pathway of 2‐nitrobenzoate via 3‐hydroxyanthranilate in Pseudomonas fluorescens strain KU‐7
Author(s) -
Hasegawa Yoshie,
Muraki Takamichi,
Tokuyama Tai,
Iwaki Hiroaki,
Tatsuno Michiaki,
Lau Peter C.K.
Publication year - 2000
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2000.tb09284.x
Subject(s) - pseudomonas fluorescens , metabolite , pseudomonas , bacteria , strain (injury) , metabolism , chemistry , metabolic pathway , biochemistry , thin layer chromatography , pseudomonadaceae , enzyme , stereochemistry , chromatography , biology , genetics , anatomy
A bacterial strain KU‐7, identified as a Pseudomonas fluorescens by 16S rDNA sequencing, was one of the 12 new isolates that are able to grow on 2‐nitrobenzoate as a sole source of carbon, nitrogen, and energy. Resting cells of KU‐7 were found to accumulate ammonia in the medium indicating that degradation of 2‐NBA proceeds through a reductive route. Metabolite analyses by thin layer chromatography and high pressure liquid chromatography indicated that 3‐hydroxyanthranilate is an intermediate of 2‐nitrobenzoate metabolism in KU‐7 cells. This offers an alternative route to 2‐nitrobenzoate metabolism since anthranilate (2‐aminobenzoate) or catechol were detected as intermediates in other bacteria. Crude extracts of KU‐7 cells converted 2‐nitrobenzoate to 3‐hydroxyanthranilate with oxidation of 2 mol of NADPH. Ring cleavage of 3‐hydroxyanthranilate produced a transient yellow product, identified as 2‐amino‐3‐carboxymuconic 6‐semialdehyde, that has a maximum absorbance at 360 nm. The initial enzymes of the 2‐nitrobenzoate degradation pathway were found to be inducible since succinate‐grown cells produced very low enzyme activities. A pathway for 2‐nitrobenzoate degradation in KU‐7 was proposed.