Isolation and characterization of a novel simazine‐degrading β‐proteobacterium and detection of genes encoding s ‐triazine‐degrading enzymes

A moderately persistent herbicide, simazine, has been used globally and detected as a contaminant in soil and water. The authors have isolated a simazine‐degrading bacterium from a simazine‐degrading bacterial consortium that was enriched using charcoal as a microhabitat. The isolate, strain CDB21, was gram‐negative, rod‐shaped (0.5–0.6 µm × 1.0–1.2 µm) and motile by means of a single polar flagellum. Based on 16S rRNA sequence analysis, strain CDB21 was identified as a novel β‐proteobacterium exhibiting 100% sequence identity with the uncultured bacterium HOClCi25 (GenBank accession number AY328574). PCR using primers that were specific for the genes of the atrazine‐degrading enzymes ( atzABCDEF ) of Pseudomonas sp. strain ADP showed that strain CDB21 also possessed the entire set of genes of these enzymes. Nucleotide sequences of the atzCDEF genes of strain CDB21 were 100% identical to those of Pseudomonas sp. strain ADP. Sequence identity of the atzA genes between these bacteria was 99.7%. The 398‐nucleotide upstream fragment of the atzB gene of strain CDB21 was 100% identical to ORF30 of Pseudomonas sp. strain ADP, and the 1526‐nucleotide downstream fragment showed 99.8% sequence similarity to the atzB gene of the pseudomonad. Copyright © 2007 Society of Chemical Industry