Communication to the Editor Degradation of Bromoxynil, Ioxynil, Dichlobenil and their Mixtures byAgrobacterium radiobacter8/4

Abstract

Degradation of three benzonitrile herbicides, bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), ioxynil (3,5-diiodo-4-hydroxybenzonitrile), dichlobenil (2, 6-dichlorobenzonitrile), and their mixtures by the soil micro-organism Agrobacterium radiobacter 8/4 was studied in batch cultures. Bromoxynil was found to be most rapidly degraded, while dichlobenil had the lowest toxicity to our strain. All transformations of studied benzonitriles were performed by the nitrile hydratase which has been shown to act on a broad range of substituted aromatic nitriles.

Characterization of a versatile nitrile hydratase of the neonicotinoid thiacloprid-degrading bacterium Ensifer meliloti CGMCC 7333

“…11401 have been reported to degrade these benzonitrile compounds through NHase/amidase systems. [7][8][9][10] The nitrogen-xing Mesorhizobium sp. F28 and its NHase degrade the solvent acetonitrile.…”

Intermediate accumulation of metabolites results in a bottleneck for mineralisation of the herbicide metabolite 2,6-dichlorobenzamide (BAM) by Aminobacter spp.

“…The degradation of dichlobenil to BAM is well documented in soil and bacterial pure cultures (Beynon and Wright 1972;Holtze et al 2006;Vosahlova et al 1997). Only two bacterial strains-Aminobacter spp.…”

Degradation and Mineralization of Nanomolar Concentrations of the Herbicide Dichlobenil and Its Persistent Metabolite 2,6-Dichlorobenzamide by Aminobacter spp. Isolated from Dichlobenil-Treated Soils

“…Two additional metabolites, ortho-chlorobenzamide and ortho-chlorobenzoic acid, have been detected in laboratory experiments with dichlobenil-treated soils (8). The metabolite BAM appears to be much more persistent than dichlobenil itself, and several studies have reported no apparent degradation of BAM in soils (1,6,8,16,40,41), aquifer sediments (2,6,36,37), or bacterial isolates (9,43). Little is therefore known about the environmental degradation of BAM.…”