title: Removal of the insecticide diazinon from liquid media by free and immobilized Streptomyces sp. isolated from agricultural soil.
abstract: From an agricultural soil that had received continuous applications of organophosphorus pesticides, 30 actinobacteria strains were isolated. Two strains, identified as Streptomyces sp. AC1-6 and Streptomyces sp. ISP4, were selected because of their tolerance to diazinon and based on the relationship between diazinon removal and microbial growth. In liquid medium with diazinon at concentrations of 25 and 50 mg L(-1), both strains were able to remove approximately 40-50% and 70-90% of the initial diazinon after 24 and 96 h of incubation, respectively. This diazinon removal was accompanied by microbial growth of the strains, an initial pH decrease, and glucose consumption in the liquid medium. Evaluation of the diazinon removal achieved by the free actinobacteria and Streptomyces sp. AC1-6 immobilized on alginate beads revealed that the immobilized cells exhibited a 60% higher diazinon removal compared with the free cells. The reusability of the encapsulated biomass was confirmed, and a diazinon removal rate of more than 50% was obtained after the second batch. This work constitutes one of the few reports that describe Streptomyces strains as diazinon degraders. Given the high diazinon removal found, the streptomycetes exhibit suitable potential as diazinon-degrading actinobacteria for elimination of diazinon from liquid residues.
authors: Department of Chemical Engineering, University of La Frontera, Temuco, Chile; Scientific and Technological Bioresource Nucleus, University of La Frontera, Temuco, Chile; Department of Chemical Science and Natural Resources, University of La Frontera, Temuco, Chile.
authors: Gabriela
authors: G
authors: Briceño
authors: María S
authors: MS
authors: Fuentes
authors: Olga
authors: O
authors: Rubilar
authors: Milko
authors: M
authors: Jorquera
authors: Gonzalo
authors: G
authors: Tortella
authors: Graciela
authors: G
authors: Palma
authors: María J
authors: MJ
authors: Amoroso
authors: Maria Cristina
authors: MC
authors: Diez
mesh_terms: D039903:Actinobacteria / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D000383:Agriculture; D000464:Alginates; D001673:Biodegradation, Environmental; D018533:Biomass; D018914:Cells, Immobilized; D003976:Diazinon / Q000378:metabolism*; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D010802:Phylogeny; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism; D013302:Streptomyces / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D012987:Soil; D012989:Soil Pollutants; D020723:Glucuronic Acid; D003976:Diazinon
keywords: Ca-alginate beads; Diazinon; Free cells; Immobilized cells; Streptomyces