Removal of two organophosphate pesticides by a bacterial consortium immobilized in alginate or tezontle

Removal of methyl parathion and tetrachlorvinphos by a bacterial consortium immobilized on tezontle-packed up-flow reactor

“…The presence of micropores allows the establishment of bacterial microcolonies (Godon et al 1997). Other characteristics of tezontle include density, 2.24-2.93 g/ml; water retention capacity, 12.91-43.3%; total porosity, 37.91-63.8%; pH, 6.88-7.35; organic material, 0%; Ca: 22.0 mg/l; Mg: 10.09 mg/l; K, 2.74 mg/l; and P: 0.31 mg/l (Yáñez-Ocampo et al 2009;Galíndez-Nájera et al 2009). The tezontle rocks were broken using a metal hammer to obtain fragments that were sifted using a 3-mm mesh sieve.…”

“…Such bacteria are capable of degrading the latter because of the presence of some enzymes, mainly related to the phosphotriesterase, which is capable of hydrolyzing OP pesticides through a nucleophilic attack on phosphorous central atom in the molecule. The hydrolysis is essential for complete degradation of OP pesticides and phosphotriesterase activity is the first and the most important step in the detoxification of OP waste or OP-contaminated sites (Yáñez-Ocampo et al 2009;Sorgob and Vilanova 2002;de la Peña et al 2006).…”

“…The degradation rates for repeated operations were observed to increase for successive batches, indicating that cells became better adapted to the reaction conditions over time (Ha et al 2009). Yáñez-Ocampo et al (2009) reported removal efficiencies of methyl-parathion (MP) and tetrachlorvinphos (TCV) of 40% and 50%, respectively, by a bacterial consortium grown in suspension in a liquid medium of mineral salts with a mixture of these pesticides. In the same study, it was found that bacterial immobilization on volcanic rock significantly increases the removal efficiency by up to 66% for both pesticides.…”

Microbial degradation of pesticide: A review

“…Several reports have documented the capability of different genera of fungi to degrade organochlorines. Bacterial enzymes have been found to achieve such detoxifying reactions (Singh et al, 1999;Yañez-Ocampo et al, 2009). The commonly used as a detoxification mechanism, especially in plants and insects, is conjugation with glutathione and this mechanism has also been reported in bacteria (Vuilleumier, 2001;Wei et al, 2001;Chaudhry et al, 2002).…”

Pesticides in the Environment: Impacts and its Biodegradation as a Strategy for Residues Treatment

“…Pesticides in the Environment: Impacts and Their Biodegradation as a Strategy for Residues Treatment 559 enzymes have been found to achieve such detoxifying reactions (Singh et al, 1999;Yañez-Ocampo et al, 2009;Yañez-Ocampo 2009). This reaction is performed by esterases or phosphotriesterases that have been described for a number of different genera of bacteria and fungi.…”