title: Biodegradation of malathion, α- and β-endosulfan by bacterial strains isolated from agricultural soil in Veracruz, Mexico.
abstract: The objective of this study was to evaluate the capacity of two bacterial strains isolated, cultivated, and purified from agricultural soils of Veracruz, Mexico, for biodegradation and mineralisation of malathion (diethyl 2-(dimethoxyphosphorothioyl) succinate) and α- and β-endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6-9-methano-2,4,3-benzodioxathiepine-3-oxide). The isolated bacterial strains were identified using biochemical and morphological characterization and the analysis of their 16S rDNA gene, as Enterobacter cloacae strain PMM16 (E1) and E. amnigenus strain XGL214 (M1). The E1 strain was able to degrade endosulfan, whereas the M1 strain was capable of degrading both pesticides. The E1 strain degraded 71.32% of α-endosulfan and 100% of β-endosulfan within 24 days. The absence of metabolites, such as endosulfan sulfate, endosulfan lactone, or endosulfan diol, would suggest degradation of endosulfan isomers through non-oxidative pathways. Malathion was completely eliminated by the M1 strain. The major metabolite was butanedioic acid. There was a time-dependent increase in bacterial biomass, typical of bacterial growth, correlated with the decrease in pesticide concentration. The CO2production also increased significantly with the addition of pesticides to the bacterial growth media, demonstrating that, under aerobic conditions, the bacteria utilized endosulfan and malathion as a carbon source. Here, two bacterial strains are shown to metabolize two toxic pesticides into non-toxic intermediates.
authors.affiliation: a Environmental Biotechnology Laboratory, Faculty of Biological and Agricultural Sciences, Universidad Veracruzana , Xalapa , Mexico.
authors.forename: Catya
authors.initials: C
authors.lastname: Jimenez-Torres
authors.affiliation: b Department of Processes and Technology , Universidad Autónoma Metropolitana-Cuajimalpa , Mexico City , Mexico.
authors.forename: Irmene
authors.initials: I
authors.lastname: Ortiz
authors.affiliation: a Environmental Biotechnology Laboratory, Faculty of Biological and Agricultural Sciences, Universidad Veracruzana , Xalapa , Mexico.
authors.forename: Pablo
authors.initials: P
authors.lastname: San-Martin
authors.affiliation: a Environmental Biotechnology Laboratory, Faculty of Biological and Agricultural Sciences, Universidad Veracruzana , Xalapa , Mexico.
authors.forename: R Idalia
authors.initials: RI
authors.lastname: Hernandez-Herrera
mesh_terms: D000383:Agriculture; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D003470:Culture Media / Q000378:metabolism; D004726:Endosulfan / Q000031:analogs & derivatives / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism; D007536:Isomerism; D008294:Malathion / Q000378:metabolism*; D008800:Mexico; D010575:Pesticides / Q000378:metabolism; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D003470:Culture Media; D007306:Insecticides; D010575:Pesticides; D012989:Soil Pollutants; D002245:Carbon Dioxide; D002244:Carbon; C544689:endosulfan sulfate; D004726:Endosulfan; D008294:Malathion
keywords: Biodegradation; Enterobacter amnigenus XGL214; Enterobacter cloacae PMM16; endosulfan; malathion