Purification and properties of a novel quizalofop-p-ethyl-hydrolyzing esterase involved in quizalofop-p-ethyl degradation by Pseudomonas sp. J-2

Abstract

Quizalofop-p-ethyl (QPE) is a post-emergence herbicide that effectively controls grass weeds and is often detected in the environment. However, the biochemical and molecular mechanisms of QPE degradation in the environment remains unclear. In this study, a highly effective QPE-degrading bacterial strain J-2 was isolated from acclimated activated sludge and identified as a Pseudomonas sp., containing the QPE breakdown metabolite quizalofop acid (QA) identified by Liquid Chromatography-Ion Trap-Mass Spectrometry (LC-IT-MSn) analysis. A novel QPE hydrolase esterase-encoding gene qpeH was cloned from strain J-2 and functionally expressed in Escherichia coli BL21 (DE3). The specific activity of recombinant QpeH was 198.9 ± 2.7 U mg−1 for QPE with K m and K cat values of 41.3 ± 3.6 μM and 127.3 ± 4.5 s−1. The optimal pH and temperature for the recombinant QpeH were 8.0 and 30 °C, respectively and the enzyme was activated by Ca2+, Cd2+, Li+, Fe3+ and Co2+ and inhibited by Ni2+, Fe2+, Ag+, DEPC, SDS, Tween 80, Triton X, β-mercaptoethanol, PMSF, and pCMB. In addition, the catalytic efficiency of QpeH toward different AOPP herbicides in descending order was as follows: fenoxaprop-P-ethyl > quizalofop-P-tefuryl > QPE > haloxyfop-P-methyl > cyhalofopbutyl > clodinafop-propargyl. On the basis of the phylogenetic analysis and multiple sequence alignment, the identified enzyme QpeH, was clustered with esterase family V, suggesting a new member of this family because of its low similarity of amino acid sequence with esterases reported previously.

The Genome Analysis of Methylobacterium populi YC-XJ1 with Diverse Xenobiotics Biodegrading Capacity and Degradation Characteristics of Related Hydrolase

“…According to the identification of metabolites, QPE was converted to QA and ethanol, consistent with the result of QpeH reported [ 24 ].…”

“…Environmental factors such as pH and temperature can affect enzyme activity and stability [ 47 ]. The optimal condition of QPEH2 was consistent with the reported characteristics of esterase QpeH [ 24 ]. Metal ions also played a key role in the activity of enzymes.…”

“…Only Fe 2+ could serve as activator for QPEH2, different from the previous report that 1 mM Ca 2+ and Cd 2+ strongly stimulated enzyme activity of QpeH from Pseudomonas sp. J-2 [ 24 ].…”

Niastella caeni sp. nov., isolated from activated sludge

“…S6b). Quizalofop-p-ethyl and diclofop-methyl are xenobiotics, and in previous studies, the two herbicides were degraded via hydrolysis by micro-organism [34,35], the diverse hydrolase genes promoted strain HX-16-21 T to evolve catabolic pathway to degrade the two herbicides. Thus, the versatile degradation abilities to aromatic compounds and herbicides enabled strain HX-16-21 T to utilize various organic pollutants in the wastewater for growth, and thus survived the wastewater environment.…”

Mineralization of the herbicide swep by a two-strain consortium and characterization of a new amidase for hydrolyzing swep

“…Microbial biodegradation is the primary pathway for the removal of organic pollutants from environments [11][12][13][14]. Numerous bacterial strains, such as species with in the genus of Variovorax [15,16], Sphingomonas sp.…”