Isolation of an Isocarbophos-Degrading Strain of Arthrobacter sp. scl-2 andIdentification of the Degradation Pathway

摘要

Isocarbophos is a widely used organophosphorus insecticidethat has caused environmental pollution in many areas.However, degradation of isocarbophos by pure cultureshas not been extensively studied, and the degradationpathway has not been determined. In this paper, a highlyeffective isocarbophos-degrading strain, scl-2, was isolatedfrom isocarbophos-polluted soil. The strain sc1-2 waspreliminarily identified as Arthrobacter sp. based on itsmorphological, physiological, and biochemical properties,as well as 16S rDNA analysis. The strain scl-2 could utilizeisocarbophos as its sole source of carbon and phosphorusfor growth. One hundred mg/1 isocarbophos could bedegraded to a nondetectable level in 18 h by scl-2 in cellculture, and isofenphos-methyl, profenofos, and phosmetcould also be degraded. During the degradation ofisocarbophos, the metabolites isopropyl salicylate, salicylate,and gentisate were detected and identified based on MS/MSanalysis and their retention times in HPLC. Transformationof gentisate to pyruvate and fumarate via maleylpyruvate andfumarylpyruvate was detected by assaying for the activitiesof gentisate 1,2-dioxygenase (GDO) and maleylpyruvateisomerase. Therefore, we have identified the degradationpathway of isocarbophos in Arthrobacter sp. scl-2 for thefirst time. This study highlights an important potentialuse of the strain scl-2 for the cleanup of environmentalcontamination by isocarbophos and presents a mechanismof isocarbophos metabolism.