Biochemical characterization of bacterial isolates capable to degrade Metsulfuron

SORAYA GABRIELA KIRIACHEK; CARLOS ALBERTO MOLDES; KATIA DURÁN; SERGIO ABASCAL; ALICIA ESTER GRASSANO

Mar del Plata

Congreso; VIII Congreso de Microbiología General; 2012

Sociedad Argentina de Microbiología General

Metsulfuron-methyl is a broad spectrum herbicide used to control broadleaf weeds. Few bacterial species are known in the biodegradation of Metsulfuron-Methyl which is also highly mobile in soils suggesting as a potential groundwater contaminant. In the present study we isolated bacteria capable to use metsulfuron as a nutritional source for growth. We used minimal medium Smith (2005) and the herbicide as a sole source of carbon and nitrogen. Then, aliquots of soil were placed in these media for the enrichment of the microbial population of Metsulfuron biodegrading. Soils came from experimental fields of Faculty of Agriculture UNLPam in which Metsulfuron was applied for three years. Twelve isolates were obtained from the upper soil (0 to 20 cm) and 7 of a lower layer (20-40 cm). Four isolates obtained were selected, based on the characteristics observed in the growth plate. They were identified as MAL1, MALM1, MALM3 and MBM3, and characterized biochemically by Gram staining, growth in Mc Conkey agar, cetrimide agar, pseudo P and F agar, and oxidase and catalase tests. The results indicate that it was possible to obtain more bacterial isolates in the surface layer than immediately below layer. Based on biochemical determinations, we can be inferred that two of the selected strains belonging to the Pseudomonas genus (MAL1 and MALM1) and two Enterobacterium genus (MALM3 and MBM3). Although biochemical assays did not identify completely, it was possible to characterize genera correlated with bacterial species found in literature.