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Applied Microbiology and Biotechnology

, Volume 54, Issue 5, pp 652–658 | Cite as

Microbial and cytoplasmic membrane-based potentiometric biosensors for direct determination of organophosphorus insecticides

  • S. Gäberlein
  • F. Spener
  • C. Zaborosch
ORIGINAL PAPER

Abstract

Potentiometric biosensors for the determination of organophosphorus (OP) insecticides were developed by applying either immobilized whole cells or cytoplasmic membrane fractions of wild-type Flavobacterium sp. on the surface of a glass pH electrode. The ability of Flavobacterium sp. to degrade OP compounds as sole carbon source was demonstrated for parathion with a degradation rate of almost 100% after 30 min and for chlorpyrifos of 33% after 48 h incubation. The products of hydrolysis of these compounds, p-nitrophenol and 3,5,6-trichloro-2-pyridinol, were accumulated in the medium and not used as substrates for growth by Flavobacterium sp. In the course of hydrolysis, which is catalyzed by organophosphorus hydrolase, two protons are released for each substrate molecule hydrolyzed. This stoichiometry forms the electrochemical basis of the potentiometric biosensors. Direct determination without previous extraction of OP was carried out in a stirred measuring cell with a pH electrode as transducer. Poly(carbamoyl sulfonate) (PCS) prepolymer, a hydrogel with good adhesive properties, was used for immobilization of whole cells and membrane-associated organophosphorus hydrolase. The sensor with cytoplasmic membrane fractions was superior to the one with whole cells and showed a linear range for paraoxon from 0.01 to 0.47 mM and 3 weeks' working stability.

Keywords

Sole Carbon Source Chlorpyrifos Direct Determination Parathion Paraoxon 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • S. Gäberlein
    • 1
  • F. Spener
    • 2
  • C. Zaborosch
    • 1
  1. 1.Institut für Chemo- und Biosensorik, Mendelstrasse 7, 48149 Münster, Germany e-mail: zaboros@uni-muenster.deDE
  2. 2.Institut für Biochemie, Universität Münster, Wilhelm-Klemm-Strasse 2, 48149 Münster, GermanyDE

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