GIULIETTI Ana Maria
congresos y reuniones científicas
Influence of physico-chemical factors on the growth of an atrazine degrading bacterial consortium
CALABRÓ LÓPEZ, A; .; CUADRADO, V.; , J.; BUSTO, V.D.;; RODRÍGUEZ TALOU J.; GIULIETTI A M
Congreso; REDBIO 2009; 2009
Atrazine is a photosynthesis inhibitor triazinic herbicide applied as pre-emergent in corn, sorghum and sugar cane among other crops. Since its half life in soil is up to 120 days and billons of tons are applied every year, the natural degradation capacity of the soil is often exceed and herbicide residues remain as environmental pollutants. In addition, run off and leaching processes can extend soil contamination to water sources, increasing the detrimental effect of this herbicide and its metabolites. The potential toxicity of atrazine motivates continuous bioremediation-directed research. The aim of this work was to study the effect of physico-chemical factors on the growth of an atrazine degrading bacterial consortium isolated from Argentinean Humid Pampa agricultural soils. Shaked flask experiments were carried out in 250 ml erlenmeyers containing 50 ml of a defined media with atrazine as sole nitrogen source. Inoculum size, stirring speed, media pH and different citrate concentrations (1,0; 2,0; 6,0 and 10,0 g/l) were studied. Cell growth and atrazine removal were monitored over time. A higher growth was observed at 10% inoculum size and at a stirring speed of 200 RPM. However, in the early phase of the culture the specific growth rate was higher at 300 RPM. The atrazine degradation began after 24 hs and a complete dissipation was observed after 144 hs at both citrate concentrations (1,0 and 2,0 g/l). No atrazine consumption was observed at higher citrate concentrations. The optimization of these physico-chemical factors will be useful to design bioaugmentation processes for bioremediation assays.