A novel 2,3-xylenol-utilizing Pseudomonas isolate capable of degrading multiple phenolic compounds

Abstract

This work characterized a novel 2,3-xylenol-utilizing Pseudomonas isolate XQ23. From 16S rRNA phylogenetic analysis, XQ23 was found to be a member of the Pseudomonas putida group. Most of its physiological characteristics also shared similarities to P. putida. Phenols were catabolized by the meta-cleavage pathway. The dependence of the specific growth rate on 2,3-xylenol concentration could be well fitted by the Haldane model, with the maximum occurring at the concentration around 180 mg l(-1). Kinetic parameters indicated that XQ23 was sensitive to 2,3-xylenol and had low affinity. Three patterns, i.e. constant, linear decline, and allometric decline, were proposed to describe the biomass yields of phenols during bacterial degradation and XQ23 under 2,3-xylenol culturing conditions followed the allometric pattern. In a mineral-salts medium supplemented with 180 mg l(-1) of 2,3-xylenol as the sole carbon and energy source, over 40% of 2,3-xylenol was turned into CO(2) to provide energy by complete oxidization.