Vortragsankündigung
gemeinsam mit
dem INSTITUT FÜR ANGEWANDTE MIKROBIOLOGIE der UNIVERSITÄT FÜR BODENKULTUR
BIODEGRADATION AND MONITORING OF ORGANOPHOSPHATE NERVE AGENTS
ASHOK MULCHANDANI
Department of Chemical and Environmental Engineering
University of California, Riverside, CA
The acute toxicity of organophosphorus neurotoxins and their widespread use in modern agricultural practices has increased public concerns. These concerns have stimulated the development of technologies to effectively treat effluents generated at both the producer and consumer levels. Additionally, the recently ratified Chemical Weapons Treaty requires all the nations to destroy all of its chemical weapons arsenal, including the organophosphorus-based nerve gases, within ten years.
Organophosphorus hydrolase (OPH) isolated from Pseudomonas and Flavobacterium has been shown to degrade organophosphates. Immobilized OPH has been used as a means to detoxify pesticides wastes. However, construction of an enzyme reactor is often very labor intensive and economically restrictive. Use of immobilized whole cell bioreactor as an alternative suffers from problems of mass transport limitations across the cell membrane.
In order to alleviate the cell membrane permeability problem, we have anchored and displayed active OPH on the cell surface of Escherichia coli using a lpp-ompA-OPH fusion. Cells with surface-expressed OPH were found to degrade organophosphates very effectively without the diffusional limitations observed in cells expressing OPH intracellularly, and also retain 100% of the original activity over one month. The cells have been surface immobilized on non-woven polypropylene fiber and porous glass beads and used in batch, sequence-batch and plug-flow bioreactors to degrade organophosphate nerve pesticides and insecticides. The cells have also been used in conjunction with potentiometric and fiber-optic transducer to develop biosensors to monitor the organophosphates rapidly and selectively.
Vortragsort:
Institut für Angewandte Mikrobiologie, 5. Stock, großer Seminarraum
1190 Wien, Muthgasse 18
Termin: 17. Juni 1999, 16:00