Enzyme-aided degradation of fenitrothion residues on eggplant (Solanum melongena L.) and tomato [(Lycopersicum esculentum (L) Darsten)]

Issue Date

10-2004

Abstract

OpDa, a phosphotriesterase from Agrobacterium radiobacter, is capable of degrading organophosphorus insecticides. Using fenitrothion as substrate, the specific activity of a crude preparation of OpDa was 151.3 umol min-1 mg-1 protein at pH 8.0. The Km and Vmax values for the enzyme-fenitrothion combination were 0.834 mM and 6.4 uM s-1, respectively. The turnover number and efficiency of the OpDa preparation were 594 s-1 and 712 M-1s-1, respectively. The enzyme was active at pH 6-8.5, but its activity was optimal at pH 8.0. Water hardness and temperature (20-35 °C) did not significantly alter enzyme activity against fenitrothion. When tested on fenitrothion-treated eggplant and tomato, a five-minute enzyme soak removed more fenitrothion residues from eggplant (53.3%) than from tomato (12.2%). Soaking eggplant in OpDa for 30 min removed 77.4% of the residual fenitrothion while a 60 min soak removed 65.8 % of the residues from tomato. The diluted enzyme preparation may be stored at room temperature for 1-2 days and then reused.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

18

Issue

2

Page

179

Document Type

Article

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

SOLANUM MELONGENA; SOLANUM LYCOPERSICUM; FENITROTHION; INSECTICIDES; AGROBACTERIUM RADIOBACTER

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