Isolation and characterisation of new Gram-negative and Gram-positive atrazine degrading bacteria from different French soils

Abstract

The capacity of 12 soils to degrade atrazine was studied in laboratory incubations using radiolabelled atrazine. Eight soils showed enhanced degradation of this compound. Twenty-five bacterial strains able to degrade atrazine were isolated by an enrichment method from 10 of these soils. These soils were chosen for their wide range of physico-chemical characteristics. Their history of treatment with atrazine was also variable. The genetic diversity of atrazine degraders was determined by amplified ribosomal restriction analysis (ARDRA) of the 16S rDNA gene with three restriction endonucleases. The 25 bacterial strains were grouped into five ARDRA types. By sequencing and aligning the 16S rDNA genes, the isolates were shown to belong to the Gram-negative species Chelatobacter heintzii, Aminobacter aminovorans, Stenotrophomonas maltophilia and to the Gram-positive genus Arthrobacter crystallopoietes. These species were not described previously as being capable of atrazine degradation. Most Gram-negative bacteria could mineralise 14 C ring labelled atrazine and carried the atzA, atzB, atzC and trzD genes. Gram-positive strains could convert atrazine to cyanuric acid and carried only the atzB and atzC genes. In this study, we describe the atrazine degradation capacities and corresponding genes in bacterial species that were not known as atrazine degraders. We report for the first time the occurrence of the trzD gene in these atrazine-mineralising bacteria and we demonstrate the potential use of colony hybridisation to isolate bacteria involved in atrazine degradation. ß

New aspects on atrazine biodegradation

“…The atrazine catabolic pathway in this bacterium contains six enzymatic steps encoded by atzABC and the atzDEF genes. The atzABC genes have been shown to be widespread and plasmid borne in a number of bacteria isolates (de Souza et al, 1998a;de Souza et al, 1998b;Rousseaux et al, 2001;Topp et al, 2000;Wackett et al, 2002). In Pseudomonas sp.…”

Untitled

“…The complete nucleotide sequencing of pADP-1 (the atrazine gene-containing plasmid of Pseudomonas ADP) revealed the arrangement and composition of atrazine degradation genes (Martinez et al, 2001). Many studies indicated that many gram-negative (Topp et al, 2000;Wackett et al, 2002) as well as gram positive atrazine-degrading bacteria contain large molecular weight plasmids containing atrazine degradation genes (Behki et al, 1993;Cai et al, 2003;Rousseaux et al, 2001;Strong et al, 2002;Vaishampayan et al, 2007). The presence of atrazine degradation genes on different size plasmids, suggests widespread of atrazine degradation genes among unrelated bacteria was not exclusively due to direct plasmid transfer.…”

Occurrence of Atrazine Biodegrading Bacterium "Ochrobactrum oryzae" In Agricultural Wastewater

“…There have been several reports on atrazine mineralization by wide varieties of bacteria such as Pseudomonas, Acinetobacter, Agrobacterium, Rhodococcus and Arthrobacter (Vibber et al, 2007;Li et al, 2008;Siripattanakul et al, 2009;Arbeli &Fuentes, 2010 andEl Sebai et al, 2012). The capability of microorganisms to utilize atrazine as a carbon, energy and/or nitrogen source was clearly demonstrated (Struthers et al, 1998;Rousseaux et al, 2001 andDevers et al, 2007). Some bacterial strains metabolized atrazine to diethylatrazine or hydroxyatrazine, while others mineralized it by cleavage the ring.…”