title: Arsenic biotransformation by cyanobacteria from mining areas: evidences from culture experiments.
abstract: Elucidating the role of cyanobacteria in the biotransformation of arsenic (As) oxyanions is crucial to understand the biogeochemical cycle of this element and indicate species with potential for its bioremediation. In this study, we determined the EC50 for As(III) and As(V) and evaluated the biotransformation of As by Synechococcus sp. through high-performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and X-ray absorption fine structure spectroscopy (XAFS). Synechococcus sp. exhibited higher sensitivity to As(III) with an EC(50, 96 h) of 6.64 mg L(-1) that was approximately 400-fold lower than that for As(V). Even though the cells were exposed to concentrations of As(III) (6 mg L(-1)) approximately 67-fold lower than those of As(V) (400 mg L(-1)), similar intracellular concentrations of As (60.0 μg g(-1)) were observed after 30 days. As(V) was the predominant intracellular As species followed by As(III). Furthermore, organic As species such as monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) were observed in higher proportions after exposure to As(III). The differential toxicity among As oxyanions indicates that determining the redox state of As in the environment is fundamental to estimate toxicity risks to aquatic organisms. Synechococcus sp. demonstrated potential for its application in bioremediation due to the high accumulation of As and production of As organic compounds notably after exposure to As(III).
authors.affiliation: Laboratório de Limnologia, Ecotoxicologia e Ecologia Aquática, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, MG, Brazil. maionewf@hotmail.com.
authors.forename: Maione W
authors.initials: MW
authors.lastname: Franco
authors.affiliation: Laboratório de Limnologia, Ecotoxicologia e Ecologia Aquática, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Fernanda A G
authors.initials: FA
authors.lastname: Ferreira
authors.affiliation: Departamento de Engenharia Metalúrgica e de Materiais, Universidade Federal do Ceará, Fortaleza, 60020-181, CE, Brazil.
authors.forename: Igor F
authors.initials: IF
authors.lastname: Vasconcelos
authors.affiliation: Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, 09210-580, SP, Brazil.
authors.forename: Bruno L
authors.initials: BL
authors.lastname: Batista
authors.affiliation: Laboratório de Limnologia, Ecotoxicologia e Ecologia Aquática, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Diego G F
authors.initials: DG
authors.lastname: Pujoni
authors.affiliation: Departamento de Farmácia Social, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Sérgia M S
authors.initials: SM
authors.lastname: Magalhães
authors.affiliation: Laboratório de Toxicologia e Essencialidade de Metais, Faculdade de Ciências Farmacêuticas de Ribeirão Preto-USP, Ribeirão Preto, 14040-903, SP, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Barbosa
authors.affiliation: Laboratório de Limnologia, Ecotoxicologia e Ecologia Aquática, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais-UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Francisco A R
authors.initials: FA
authors.lastname: Barbosa
mesh_terms: D001151:Arsenic / Q000032:analysis / Q000378:metabolism; D001152:Arsenicals / Q000032:analysis / Q000378:metabolism*; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D008906:Mining; D046940:Synechococcus / Q000378:metabolism*
chemical_list: D001152:Arsenicals; D001151:Arsenic
keywords: Arsenic speciation; Bioremediation; Cyanobacteria; Growth inhibition; Synechococcus