Abstract: Compositions and methods for catalytic buffering of enzymatic decontamination reactions are provided. Enzymatic decontamination of organophosphorus or organohalogen compounds generates acidic reaction products that precipitously reduce the pH of the medium, thus impairing activity of the decontaminating enzymes. Catalytic buffering, that is, the use of an enzyme to produce ions from a substrate to modulate pH, can provide effective pH control. The compositions provided here include urease enzymes with mutations in the alpha subunit of the urease holoenzyme. These mutant ureases maintain urease activity in the presence of fluoride ions, which are organophosphorus and organohalogen hydrolysis products that otherwise inhibit urease activity. The fluoride-resistant ureases act as effective catalytic buffers during organofluorophosphorus hydrolysis reactions. Methods for using the fluoride-resistant ureases in enzymatic decontamination are also provided.

Abstract: A biodegradation process for the organophosphonate product of Sarin (O-isopropyl methylphosphonofluoridate) hydrolysis, i.e., isopropylmethylphosphonate (IMPA). This process provides a feasible biodegradation demilitarization alternative to Sarin incineration. Public opposition of nerve agent incineration is widespread, and alternative methods are sought to help the U.S. Army meet the 2007 demilitarization deadline imposed by the Chemical Weapons Convention. This process uses a two-step approach to IMPA biodegradation. In the first step, a concentrated IMPA solution is used as the sole nutritional carbon and phosphorus source for microbial cultures. The second step involves diluting the culture and adding an inexpensive carbon source to encourage bacterial phosphate assimilation. The biodegradation typically involves a consortium of microorganisms comprising Methylobacterium radiotolerans GB21, Agrobacterium tumefaciens GB2GA, Klebsiella oxytoca GB2CS, GB272, Aureobacterium sp.

Abstract: A biodegradation process for the organophosphonate product of Sarin (O-isopropyl methylphosphonofluoridate) hydrolysis, i.e., isopropylmethylphosphonate (IMPA). This process provides a feasible biodegradation demilitarization alternative to Sarin incineration. Public opposition of nerve agent incineration is widespread, and alternative methods are sought to help the U.S. Army meet the 2007 demilitarization deadline imposed by the Chemical Weapons Convention. This process uses a two-step approach to IMPA biodegradation. In the first step, a concentrated IMPA solution is used as the sole nutritional carbon and phosphorus source for microbial cultures. The second step involves diluting the culture and adding an inexpensive carbon source to encourage bacterial phosphate assimilation. The biodegradation typically involves a consortium of microorganisms comprising Methylobacterium radiotolerans GB21, Agrobacterium tumefaciens GB2GA, Klebsiella oxytoca GB2CS, GB272, Aureobacterium sp.