Co-metabolic biodegradation of acetamiprid by Pseudoxanthomonas sp. AAP-7 isolated from a long-term acetamiprid-polluted soil

Abstract

An AAP-degrading bacterium, AAP-7, was isolated from AAP-polluted soil. AAP-7 was identified as Pseudoxanthomonas sp. on the basis of the comparative analysis of 16S rDNA sequences. The strain was able to transformate more than 80% AAP by means of co-metabolism and degraded AAP via hydrolysis or demethylation to form (E)-3-(((6-chloropyridin-3yl)methyl)(methyl)amino)acrylonitrile and N-((6-chloropyridin-3yl)methyl)-N-methylprop-1-en-2-amine, both of which transformed into ultimate product, which was 1-(6-chloropyridin-3yl)-N-methylmethanamine. A novel degradation pathway was proposed based on these metabolites. AAP could be transformed with a maximum specific degradation rate, half-saturation constant and inhibit constant of 1.775/36 h, 175.3 mg L(-1), and 396.5 mg L(-1), respectively, which proved that the degradation rate of AAP could be restrained at high AAP concentration. This paper highlights a significant potential use of co-metabolic cultures of microbial cells for the cleanup of AAP-contaminated soil.