Evidence for Enhanced Dissipation of Chlorpyrifos in an Agricultural Soil Inoculated with Serratia Rubidaea Strain ABS 10

Important mineralization of 14 C-chlorpyrifos was found in a Tunisian soil exposed repeatedly to this insecticide. A bacterial strain able to grow in minimal salt medium (MSM) supplemented with 25 mg L − 1 of chlorpyrifos was isolated from this soil. It was characterized as Serratia rubidaea strain ABS 10 using morphological and biochemical analyses, as well as 16S rRNA sequencing. In liquid culture S. rubidaea stain ABS 10 was able to almost entirely dissipate chlorpyrifos within 48 hours of incubation. Although, S. rubidaea strain ABS 10 was able to grow on MSM supplemented with chlorpyrifos and to dissipate it in liquid culture, it was not able to mineralize 14 C-chlorpyrifos. Therefore, one can conclude that the dissipation capability of this bacteria might be attributed to its capacity to adsorb CHL. In both non-sterile and sterile soil inoculated with S. rubidaea strain ABS 10 , chlorpyrifos was more rapidly dissipated than in respective controls.