Pseudomonas sp. strain HBP1 Prp degrades 2-isopropylphenol (ortho-cumenol) via meta cleavage

Abstract

Pseudomonas sp. strain HBP1 Prp grew on 2-isopropylphenol as the sole carbon and energy source with a maximal specific growth rate of 0.14 h-1 and transient accumulation of isobutyric acid. Oxygen uptake experiments with resting cells and enzyme assays with crude-cell extracts showed that 2- isopropylphenol was catabolized via a broad-spectrum meta cleavage pathway. These findings were confirmed by experiments with partially purified enzymes. Identification of 3-isopropylcatechol and 2-hydroxy-6-oxo-7-methylocta-2,4- dienoic acid as the products of the initial monooxygenase reaction and the subsequent extradiol ring cleavage dioxygenase reaction, respectively, was based on gas chromatography-mass spectrometry analysis of the corresponding trimethylsilyl derivatives. The meta cleavage product hydrolase hydrolyzed 2- hydroxy-6-oxo-7-methylocta-2,4-dienoic acid (meta cleavage product of 2- isopropylphenol) to isobutyric acid and 2-hydroxypent-2,4-dienoic acid.