Isolation of a Glyphosate-Metabolizing Variety of Acinetobacter Johnsonii: Preliminary Evidence of C-P Lyase Activity

The use of the organophosphate herbicide glyphosate has caused environmental contamination and its implications in negative health effects have also been reported. The metabolism of glyphosate by microorganisms, with the consequent transformation into non-toxic compounds, known as bioremediation, is presented as the most feasible decontamination option. Glyphosate metabolism mainly comprises two pathways, which lead to the production of sarcosine and inorganic phosphate and aminomethylphosphonic acid (AMPA) and glyoxylate respectively. In the present work, an organism was isolated. Molecular identification by 16S rRNA gene amplification, confirmed the isolate as Acinetobacter Johnsonii, which after 240 hours of adaptation, utilized glyphosate as a sole phosphate source. Significantly, the isolate exhibited C-P lyase activity, a pathway that avoids the formation of the toxic byproduct AMPA. Despite the observed presence of endogenous phosphate reserves, glyphosate supported growth was not inhibited. This suggested that the adapted variant Acinetobacter Johnsonii strain 1.8 (accession number PX671463.1) was insensitive to phosphate mediate repression of phosphonate metabolism, an advantegous characteristics for bioremediation in high phosphate agricultural settings. This work constitutes the first report of an Acinetobacter Johnsonii variant capable of metabolize glyphosate.