Degradation of ‘Diazinon’ by Synergistic Microbial Action

Abstract

THE mechanisms and pathways involved in the degradation of pesticides have received more attention as efforts to define the extent of environmental contamination by these chemicals have increased. Complex interrelationships have been found between the soil microflora and organophosphate insecticides, such as ‘Diazinon’^1–3. In the case of ‘Diazinon’, utilization of the chemical by an Arthrobacter sp. and a Streptomyces sp. has been shown to alter the existing microbial population balance by stimulating a selective enrichment of these species³. Labelled carbon dioxide was evolved when ‘Diazinon’ labelled on the C1 of the ethyl ester was incubated with a species of Arthrobacter for 24 h. Similarly, labelled carbon dioxide was given off when the same labelled insecticide was injected into soil which contained an unidentified microbial population. We had been concerned with the pyrimidinyl ring of the ‘Diazinon’ molecule, and the possible differentiation of the degradative pathways associated with microbial metabolism by which the Arthrobacter and the Streptomyces that emerged as the predominant successive microfloral forms in soil treated with ‘Diazinon’ could attack the ring moiety of this compound.