Análisis de la capacidad de biodegradación de glifosato a partir de microorganismos aislados del suelo

Abstract

In this investigation, the glyphosate biodegradation was analyzed from isolated microorganisms obtained from glyphosate contaminated soil. Ten glyphosate-degrading bacterial strains from agricultural soils located in Puerto Quito, Otavalo and Pintag were isolated and characterized, macro- and microscopically. A pre-selection of incubated strains with 1 % v/v of glyphosate was made, afterwards three strains were chosen (PG54P01, PG54P04, PG54T04), which showed a high growth rate evidenced by UV-Vis spectrophotometry, in comparison to the rest of the bacteria. The taxonomic identification was achieved using miniaturized API tests and the CrystalMind software, determining that the strain PG54P04 corresponds to the species Burkholderia cepacia with 99,74 % certainty, while the strain PG54T04 corresponds to the species Escherichia coli with a 97,61 % certainty. Strain PG54P01 could not be identified by this method. Through a statistical analysis it was determined that PG54P01 had a maximum tolerance at 0,40 % (v/v) glyphosate concentration, whereas, PG54P04 and PG54PT04 had a maximum tolerance at 0,80 % (v/v) glyphosate concentration, PG54P04 is the most tolerant strain at different concentrations. Furthermore, the biodegradation capacity, in 5 and 15 days, was analyzed with Thin Layer Chromatography (TLC), showing a greater degradation rate after 15 days of testing.