Characterization of a Nocardioides-based, atrazine-mineralizing microbial colony isolated from Japanese riverbed sediment

Abstract

A multiple-member microbial colony (designated A14N) capable of mineralizing the herbicide atrazine has been isolated from Japanese riverbed sediment. We have determined the enzymes involved in the degradation route and the species composition of the colony. A14N converted atrazine to cyanuric acid via hydroxyatrazine and N-isopropylammelide as intermediates. Furthermore, A14N characteristically had the ability to cleave the triazine ring of cyanuric acid. A14N harbours genes coding atrazine-degrading enzymes, which are highly similar to those previously described: trzN, atzB and atzC. At least three phylogenetically different species, Nocardioides sp., Mycobacterium sp. and Leptospira sp. were present in A14N. Among these, Nocardioides sp. was closely related to the atrazine-degrading Nocardioides sp. strains previously isolated from agricultural soils. Thus, Nocardioides sp. in A14N could also be responsible for the degradation of atrazine to cyanuric acid. © Pesticide Science Society of Japan.