title: Impact of bio-palladium nanoparticles (bio-Pd NPs) on the activity and structure of a marine microbial community.
abstract: Biogenic palladium nanoparticles (bio-Pd NPs) represent a promising catalyst for organohalide remediation in water and sediments. However, the available information regarding their possible impact in case of release into the environment, particularly on the environmental microbiota, is limited. In this study the toxicity of bio-Pd NPs on the model marine bacterium V. fischeri was assessed. The impacts of different concentrations of bio-Pd NPs on the respiratory metabolisms (i.e. organohalide respiration, sulfate reduction and methanogenesis) and the structure of a PCB-dechlorinating microbial community enriched form a marine sediment were also investigated in microcosms mimicking the actual sampling site conditions. Bio-Pd NPs had no toxic effect on V. fischeri. In addition, they had no significant effects on PCB-dehalogenating activity, while showing a partial, dose-dependent inhibitory effect on sulfate reduction as well as on methanogenesis. No toxic effects by bio-Pd NPs could be also observed on the total bacterial community structure, as its biodiversity was increased compared to the not exposed community. In addition, resilience of the microbial community to bio-Pd NPs exposure was observed, being the final community organization (Gini coefficient) of samples exposed to bio-Pd NPs similar to that of the not exposed one. Considering all the factors evaluated, bio-Pd NPs could be deemed as non-toxic to the marine microbiota in the conditions tested. This is the first study in which the impact of bio-Pd NPs is extensively evaluated over a microbial community in relevant environmental conditions, providing important information for the assessment of their environmental safety.
authors.affiliation: Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, 40131 Bologna, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Nuzzo
authors.affiliation: Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
authors.forename: Baharak
authors.initials: B
authors.lastname: Hosseinkhani
authors.affiliation: Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.affiliation: Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, 40131 Bologna, Italy. Electronic address: giulio.zanaroli@unibo.it.
authors.forename: Giulio
authors.initials: G
authors.lastname: Zanaroli
authors.affiliation: Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Via Terracini 28, 40131 Bologna, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Fava
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects*; D002384:Catalysis; D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism; D019015:Geologic Sediments / Q000382:microbiology*; D054879:Halogenation; D053768:Metal Nanoparticles / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry* / Q000494:pharmacology*; D011078:Polychlorinated Biphenyls / Q000737:chemistry / Q000378:metabolism
chemical_list: D004785:Environmental Pollutants; D010165:Palladium; D011078:Polychlorinated Biphenyls
keywords: Bacterial community structure; Bio-Pd NPs; Ecotoxicity; Marine sediment; Nanoparticles