Identification of bacterial strains tolerant to pesticides from agricultural soils

Abstract

Several microorganisms are able to degrade pollutants such as pesticides due to their metabolic potential. In this study, bacteria were isolated and identified from agricultural soils, which were able to tolerate and use pesticides as sole carbon and energy source. Five of the most commonly used chemical pesticides (dimethylamines, tri-isopropanolamines, glyphosate salts, atrazine and carbofuran) were evaluated at different concentrations using two culture media; TY (Triptona / Yeast Extract) and Bushnell Haas (FLUKA). From the TY medium, 13 isolates with a tolerance to 0.05, 1.0, 5.0 and 10% pesticide were isolated. Isolates with a maximum tolerance of 1% for glyphosate and dimethylamine salts were identified as Bacillus, Microbacterium and Bordetella. Strains with maximum tolerance to 5% and 10% salts of tri-isopropanolamines, atrazine and carbofuran belong to the genera Pseudomonas, Enterobacter, Stenotrophomonas and Achromobacter. On the other hand, 9 isolates were obtained in Bushnell Haas medium, which showed a minimum tolerance of 0.05% and a maximum of 0.5% for glyphosate, 2.5% tolerance for dimethylamine salts, and 5% tolerance for atrazine and carbofuran. These isolates belong to five different genera; Pseudomonas, Stenotrophomonas, Brevundimonas, Achromobacter and Enterobacter.