Biogradation of chlorpyrifos for natives microalgas of Mendoza lakes

FERRARI MM; RAY AM; FUNES M; BUSTOS D; BUSTOS D; DA SILVA SM

Congreso; XXXVII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2019

Pesticides go downstream to the aquatic ecosystem causing an imbalance and alteration in the way of living of the communities settled there. Chlorpyrifos (CPF) is one of the most commonly used organophosphorus insecticides in Argentina, although in 2000 the United States Environmental Protection Agency (USEPA) rigorously regulates its use. Microalgae play a vital role in ecosystem stability, which is why, they are the first to respond to a change in their environment. Under certain conditions some microalgae can develop in environments where autotrophic metabolism is not viable, so heterotrophic cultures can be used to study some metabolic aspects of them. Previous works shows that these organisms react quickly to environmental changes caused by organophosphorus contamination. This is why the aim of this work, is to evaluate the biodegradation of the CPF by a native strain Chlorophyta under two different incubation conditions, light and total darkness. Therefore, a unialgal culture was made in Bold Basal (BBM) medium from an isolated strain of an urban lake in Mendoza province and was harvested in its exponential growth phase. Stock solutions of CPF were prepared from commercial formulations, and 10ppm were added to the algae culture. These cultures, with and without CPF, were incubated at 30°C for 6 days in light and darkness conditions, under continuous agitation. The biodegradation of CPF was monitored employing HPLC-DAD. The results demonstrated that the biodegradation in darkness is 70% more effective than in light conditions. It was also found that, the occurrence of sub-products of biodegradation is below the detection and quantification limits.