title: Bioaugmentation and rhizosphere-assisted biodegradation as strategies for optimization of the dissipation capacity of biobeds.
abstract: Biobeds are on-farm biodepuration systems whose efficiency rely on their high pesticide biodegradation capacity. We evaluated two optimization strategies, bioaugmentation and/or rhizosphere-assisted biodegradation, to maximize the dissipation capacity of biobeds. Iprodione was used as a model pesticide. Its dissipation and metabolism was determined in a biobed packing material inoculated with an iprodione-degrading Arthrobacter strain C1 (bioaugmentation, treatments B+C1) and/or seeded with ryegrass (rhizosphere-assisted biodegradation, treatments B+P). The impact of those strategies on the activity and composition of the microbial community was determined. Bioaugmentation accelerated the dissipation of iprodione which was further enhanced in the bioaugmented, rhizosphere-assisted treatment (treatment B+P+C1, Half-life (DT50) = 3.4 d), compared to the non-bioaugmented, non rhizosphere-assisted control (DT50= 9.5 d, treatment B). Bioaugmentation resulted in the earlier formation of intermediate formation of metabolites I (3,5-dichlorophenyl-carboxamide), II (3,5-dichlorophenylurea acetate) and 3,5-dichloroaniline (3,5-DCA). The latter was further dissipated by the indigenous microbial community. Acid phosphatase (AP) and β-glucosidase (GLU) were temporarily stimulated in rhizosphere-assisted treatments, whereas a stimulation of the fluorescein diacetate (FDA) hydrolytic activity in the bioaugmented treatments coincided with the hydrolysis of iprodione. q-PCR showed that changes in the abundance of alpha-proteobacteria and firmicutes was driven by the presence of rhizosphere while bioaugmentation had no significant effect.
authors.affiliation: Biotechnological Research Center Applied to the Environment (CIBAMA), Universidad de La Frontera, Temuco, Chile.
authors.forename: M
authors.initials: M
authors.lastname: Campos
authors.affiliation: Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Viopolis 41500, Greece.
authors.forename: C
authors.initials: C
authors.lastname: Perruchon
authors.affiliation: Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Viopolis 41500, Greece.
authors.forename: P A
authors.initials: PA
authors.lastname: Karas
authors.affiliation: Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Viopolis 41500, Greece.
authors.forename: D
authors.initials: D
authors.lastname: Karavasilis
authors.affiliation: Chemical Engineering Department, Universidad de La Frontera, Chile.
authors.forename: M C
authors.initials: MC
authors.lastname: Diez
authors.affiliation: Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Viopolis 41500, Greece. Electronic address: dkarpouzas@bio.uth.gr.
authors.forename: D G
authors.initials: DG
authors.lastname: Karpouzas
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics; D000814:Aniline Compounds / Q000378:metabolism; D001173:Arthrobacter / Q000378:metabolism; D001673:Biodegradation, Environmental; D000072480:Farms; D006207:Half-Life; D006827:Hydantoins / Q000378:metabolism* / Q000493:pharmacokinetics; D008129:Lolium / Q000378:metabolism; D010575:Pesticides / Q000378:metabolism* / Q000493:pharmacokinetics; D058441:Rhizosphere; D018505:Waste Management / Q000379:methods*; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D000814:Aniline Compounds; D006827:Hydantoins; D010575:Pesticides; D000620:Aminoimidazole Carboxamide; D000135:Acid Phosphatase; D001617:beta-Glucosidase; C037267:3,5-dichloroaniline; C033148:iprodione
keywords: 3,5-Dichloraniline (3,5-DCA); Bioaugmentation; Iprodione; Microbial abundance; Microbial activity; Rhizosphere-assisted biodegradation