title: Comparative metagenomic analysis of PAH degradation in soil by a mixed microbial consortium.
abstract: In this study, we used a taxonomic and functional metagenomic approach to analyze some of the effects (e.g. displacement, permanence, disappearance) produced between native microbiota and a previously constructed Polycyclic Aromatic Hydrocarbon (PAH)-degrading microbial consortium during the bioremediation process of a soil polluted with PAHs. Bioaugmentation with a fungal-bacterial consortium and biostimulation of native microbiota using corn stover as texturizer produced appreciable changes in the microbial diversity of polluted soils, shifting native microbial communities in favor of degrading specific populations. Functional metagenomics showed changes in gene abundance suggesting a bias towards aromatic hydrocarbon and intermediary degradation pathways, which greatly favored PAH mineralization. In contrast, pathways favoring the formation of toxic intermediates such as cytochrome P450-mediated reactions were found to be significantly reduced in bioaugmented soils. PAH biodegradation in soil using the microbial consortium was faster and reached higher degradation values (84% after 30 d) as a result of an increased co-metabolic degradation when compared with other mixed microbial consortia. The main differences between inoculated and non-inoculated soils were observed in aromatic ring-hydroxylating dioxygenases, laccase, protocatechuate, salicylate and benzoate-degrading enzyme genes. Based on our results, we propose that several concurrent metabolic pathways are taking place in soils during PAH degradation.
authors.affiliation: Instituto Politécnico Nacional, CIBA-Tlaxcala, Carretera Estatal San Inés Tecuexcomac-Tepetitla Km 1.5, Tepetitla, Tlaxcala. 90700, Mexico.
authors.forename: German
authors.initials: G
authors.lastname: Zafra
authors.affiliation: RIKEN Center for Integrative Medical Sciences, Laboratory for Integrated Bioinformatics, Tsurumi-ku 230-0045, Yokohama, Kanagawa, Japan.
authors.forename: Todd D
authors.initials: TD
authors.lastname: Taylor
authors.affiliation: Instituto Politécnico Nacional, CIBA-Tlaxcala, Carretera Estatal San Inés Tecuexcomac-Tepetitla Km 1.5, Tepetitla, Tlaxcala. 90700, Mexico. Electronic address: aabsalon@ipn.mx.
authors.forename: Angel E
authors.initials: AE
authors.lastname: Absalón
authors.affiliation: Instituto Politécnico Nacional, CIBA-Tlaxcala, Carretera Estatal San Inés Tecuexcomac-Tepetitla Km 1.5, Tepetitla, Tlaxcala. 90700, Mexico. Electronic address: dcortes@ipn.mx.
authors.forename: Diana V
authors.initials: DV
authors.lastname: Cortés-Espinosa
mesh_terms: D001419:Bacteria / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D001673:Biodegradation, Environmental; D019295:Computational Biology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D052918:Environmental Restoration and Remediation; D005658:Fungi / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D056186:Metagenomics; D064307:Microbiota / Q000235:genetics*; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D012988:Soil Microbiology; D012989:Soil Pollutants
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D012989:Soil Pollutants; D003577:Cytochrome P-450 Enzyme System
keywords: Aromatic-ring-hydroxylating dioxygenases; Metagenomics; Microbial consortium; Polycyclic aromatic hydrocarbons (PAHs); Soil bioremediation