Isolation of filamentous fungi with the ability to degrade imidacloprid insecticide from contaminated soil

AGUIRRALDE MELISSA CELESTE; MAZUCOTELLI, CINTIA ; PÉREZ, DÉBORA J; WOLSKI, ERIKA A.

Panamá

Congreso; XI CONGRESO LATINOAMERICANO DE MICOLOGÍA (XI CLAM); 2023

Asociación Latinoamericana de Micología

Imidacloprid is a neonicotinoid insecticide, widely used for the control of sucking insects in various horticultural crops, including strawberries, widespread in the City of Mar del Plata (Buenos Aires, Argentina). Given the physicochemical and environmental properties of imidacloprid (high solubility, low volatility and moderate persistence in soils), soil and water contamination is of great environmental concern. In this sense, fungal degradation emerges as a potential tool to reduce imidacloprid levels in soils and wastewater, and thus mitigate its subsequent impacts. The objective of this work was to isolate fungal strains with the potential to degrade imidacloprid, from a soil cultivated with strawberries with a history of application of this insecticide.Composite soil samples were taken. Subsamples of 20 g were homogenized in 0.1% peptone water and decimal serial dilutions were made. Then they were inoculated in Petri dishes containing potato glucose agar supplemented with increasing concentrations of Imidacloprid. The plates were incubated for 7 days, in the dark at 28°C. Subsequently, to evaluate the biodegradation of Imidacloprid, the strains capable of growing and tolerating high concentrations of it were inoculated in a minimal mineral salts medium with glucose (5 g/L) and imidacloprid (20 mg/L), and incubated in the dark at 28°C at 150rpm. The same procedure was followed with the control (non-inoculated). After 20 days, the presence of Imidacloprid was analyzed by HPLC-DAD (270 nm). Of the 13 isolates tolerant to imidacloprid, only 2 showed the ability to degrade it. The strains called A10 and B1, showed 52% and 68.8% degradation, respectively.The results showed that the A10 and B1 strains could be used in the future, as tools for bioremediation of soils contaminated with Imidacloprid and the wastewater treatment.