Page 45 - FoodFocusThailand No.165 December 2019

SAFETY ALERT

depends on several factors including type of Role of Enzyme for Bioremediation and Insecticide Removal from
vegetable and fruit, chemical properties and Vegetables and Fruits
contamination concentration of the pesticide. Since some microbial enzymes exhibit high efficacy and specificity for pesticide degradation
Despite the efficacy of these techniques, some and reduce the toxicity of the chemical, these enzymes have been applied for bioremediation
may cause adverse effect to quality of the in order to clean up the pesticide contaminated agricultural areas (Sharma et al., 2018). In
addition, these enzymes can be formulated into a vegetable-fruit cleaning agent. The
produces, e.g. withering, change of color or formulated enzyme not only removes the pesticide contaminated on the produce surface,
taste. but it also breaks down these toxic chemicals effectively reducing their toxicity. There are
3 groups of effective organophosphate-degrading enzymes including organophosphate
Pesticide Fate and Degradation in hydrolase (Oph), methylparathion hydrolase (Mph), and phosphohydrolase (GpdQ). All of
Environment them are intracellular enzymes catalyzing hydrolysis with different activity and specificity
In environment, pesticides including towards organophosphate insecticides.The formulated enzyme is advantageous because
insecticides may be stable or mitigated by it is not only solubilize the chemicals from the produces’ surface, but it also effectively
breaks down the pesticide chemical structure reducing the toxicity. It is a safe, reusable
physical mechanism (e.g. adsorption to soil natural substance without any foam-forming agent. It is environmentally friendly agent when
particles, vaporization), chemical reaction, and discharged into environment.
biological degradation by microbes (Morillo &
Villaverde, 2017). Factors involving pesticide
depletion in nature include type and chemical
properties of the pesticide, soil and water
characteristics, pesticide concentration,
temperature, pH, sunlight intensity and
availability as well as biodegradation ability of
surrounding microbes.
A study of organophosphate depletion in
o
the controlled environment (25 C, pH 7.0)
showed that this group of chemical can be
degraded by microbes faster than that using
chemical or physical treatment (Ragnarsdottir,
2000). Bacteria and fungi with organophosphate
insecticide bioodegradation capability are
ubiquitous in nature. For example, a Gram
positive bacterium: Bacillus pumilus strain
C2A1 is chlorpyrifos-degradaing microbe,
while Trichoderma atroviride is dichlorvos-
degrading fungal strain (Marican & Duran-Lara,
2018). Pesticide biodegradation capability of
these microbe is actually generated by their
enzymes induced in response to pesticide
exposure. Enzyme is a catalytic protein
catalyzing biological reactions in living cells to
synthesize biomolecules, produce cell energy
as well as degrade toxic compounds such as
organophosphate insecticides.

DEC 2019 FOOD FOCUS THAILAND 45

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