Glyphosate acetylation as a specific trait of Achromobacter sp. Kg 16 physiology.

The growth parameters of Achromobacter sp. Kg 16 (VKM B-2534 D), such as biomass and maximum specific growth rate, depended only on the source of phosphorus in the medium, but not on the carbon source or the presence of growth factors. With glyphosate as a sole phosphorus source, they were still 40–50 % lower than in media supplemented with orthophosphate or other organophosphonate-methylphosphonic acid. At the first time process of glyphosate acetylation and accumulation of acetylglyphosate in culture medium were revealed in this strain. Acetylglyphosate isolated from cultural liquid was identified by mass spectroscopy; its mass spectrum fully corresponded with that of chemically synthesized acetylglyphosate. Even poorer growth was observed in media with acetylglyphosate: although the strain was able to utilize this compound as a sole source of phosphorus, the maximum biomass was still 58–70 % lower than with glyphosate. The presence of acetylglyphosate in culture medium could also hinder the utilization of glyphosate as a phosphorus source. Therefore, the acetylation of glyphosate may be a specific feature of Achromobacter sp. Kg 16 responsible for its poor growth on this compound.