Furthering the Enzymatic Destruction of Nerve Agents

This study was conducted to investigate the biodegradation potential of neutralized organophosphorus nerve agents: O-ethyl-S-(2-diisopropyl-aminoethyl) methylphosphonothioate (VX), Sarin (GB), Soman (GD), and O-cyclohexyl methylphosphonofluoridate (GF). Removing labile leaving groups from these compounds can be accomplished chemically (e.g. alkali) or enzymatically (by a variety of hydrolases) resulting in stable ionic methylphosphonate esters. Glyphosate utilizing Burkholderia caryophilli PG2982 was found to use for growth (as the sole phosphorus sources) low concentrations of ethyl-, isopropyl-, and pinacolyl methylphosphonates (EMPn, IMPn, and PMPn alkali treatment products of VX, GB, and GD, respectively). Partially purified enzyme was obtained from crude extracts of the B. caryophilli PG2982 strain and tested for esterase activity against these phosphonate esters in addition to isobutyland cyclohexyl methylphosphonates (iBMPn and CMPn alkali treatment products of Russian-VX and GF, respectively). Derivatized substrates and products were monitored by GC-FPD. Esterase activities were observed in the order: iBMPn>CMPn>EMPn>IMPn>PMPn. These results demonstrate the potential use of B. caryophilli derived enzyme(s) in furthering the destruction of these neurotoxic chemical compounds. This could be an important factor for the US and other nations in attempting to meet the requirements of the 1993 Chemical Weapons Convention agreement to destroy all chemical warfare agents within ten years of ratification (April 2007 for the US).