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Title: Biodegradation kinetics of neutralized Sarin by two different consortia

Sarin (o-isopropyl methylphosphonofluoridate), one of the several highly toxic chemical warfare agents, can be readily neutralized in sodium hydroxide solution forming large quantities of brine solution containing IMPA (o-isopropyl methylphosphonic acid) and sodium fluoride that must be further processed and disposed. Two mixed cultures were successfully acclimated to use IMPA as a phosphorus source. The medium formula was chosen to provide the reactors with adequate alternative carbon sources so that the only limiting factor of the bacterial growth is phosphorus. Kinetic studies of the two cultures both in suspended and encapsulated forms were done with the initial IMPA concentrations ranged from 15 mg/L to 1,280 mg/L. Kinetic parameters were estimated based on IMPA and biomass concentrations measured over time using Monod equation and the least square method. For both cultures IMPA was not inhibitive under the tested conditions. For the free cells, n{sub max} was 131.3 mg/l/day for the APG swamp microorganisms and 120.9 mg/l/day for the soil extracted microorganisms. For the encapsulated cells, n{sub max} was 81.7 mg/l/day for the APG swamp microorganisms and 67.1 mg/l/day for the soil extracted microorganisms. The smaller values of n{sub max} for both types of the encapsulated microorganisms were very likely caused bymore » substrate and nutrient transport limitation. For both cultures and both cell forms, it was observed that the degradation of IMPA formed MPA and phosphate sequentially. This led to the proposal of an IMPA biodegradative pathway involving an organophosphate hydrolase catalyzed reaction forming MPA. This would then be followed by C-P lyase catalyzed reaction transforming MPA to orthophosphate.« less
Authors:
; ; ; ; ;  [1]
  1. Texas A and M Univ., College Station, TX (United States). Dept. of Civil Engineering
Publication Date:
OSTI Identifier:
462550
Report Number(s):
CONF-961149--
Journal ID: ISSN 1087-8939; TRN: IM9719%%20
Resource Type:
Conference
Resource Relation:
Conference: 17. annual meeting of the Society of Environmental Toxicology and Chemistry: partnerships for the environment - science, education, and policy, Washington, DC (United States), 17-21 Nov 1996; Other Information: PBD: 1995; Related Information: Is Part Of SETAC 17. annual meeting -- Abstract book. Partnerships for the environment: Science, education, and policy; PB: 378 p.
Publisher:
Society of Environmental Toxicology and Chemistry, Pensacola, FL (United States)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; 56 BIOLOGY AND MEDICINE, APPLIED STUDIES; CHEMICAL WARFARE AGENTS; BIODEGRADATION; REMEDIAL ACTION; ENZYME ACTIVITY; HYDROLASES; LYASES; METABOLISM; SOILS