title: Isolation and identification of indigenous prokaryotic bacteria from arsenic-contaminated water resources and their impact on arsenic transformation.
abstract: Arsenic is a known human carcinogen. Arsenite [As(III), H3AsO3] and arsenate [As(V), H2AsO4-and HAsO42-] are the two predominant compounds of As found in surface water and groundwater. The aim of this study was to explore a bioremediation strategy for biotransformation of arsenite to arsenate by microorganisms. In this study, Babagorgor Spring, located west of Iran, was selected as the arsenic-contaminated source and its physicochemical characteristics and in situ microbiological composition were analyzed. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) analysis indicated that the arsenic level was 614μg/l. Fourteen arsenic tolerant indigenous bacteria were isolated from arsenic-contaminated water using chemically defined medium (CDM), supplemented with 260-3900mg/l arsenite and 1560-21800mg/l arsenate. Among the isolates, a strain As-11 exhibited high ability of arsenic transformation. Biochemical tests were used for bacterial identification and confirmation was conducted by 16S rRNA sequence analysis. Results confirmed that As-11 was related to the genus Pseudomonas. This bacterium showed maximum tolerable concentration to arsenite up to 3250mg/l and arsenate up to 20280mg/l. Under heterotrophic conditions, the bacterium exhibited 48% of As(III) and 78% of As(V) transformation from the medium amended with 130 and 312mg/l of sodium arsenite and sodium arsenate, respectively. Moreover, under chemolithotrophic conditions, bacterium was able to transform 41% of 130mg/l of As(III) from the medium amended with nitrate as the terminal electron acceptor. Pseudomonas strain As-11 was reported as an arsenic transformer, for the first time.
authors.affiliation: Environmental Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Mohammad Ahmadi
authors.initials: MA
authors.lastname: Jebelli
authors.affiliation: Environmental Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Afshin
authors.initials: A
authors.lastname: Maleki
authors.affiliation: Extremophiles Laboratory, Department of Microbiology, Faculty of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Amoozegar
authors.affiliation: Dietary Supplement and Probiotic Research Center, Alborz University of Medical Sciences, Karaj, Iran.
authors.forename: Enayatollah
authors.initials: E
authors.lastname: Kalantar
authors.affiliation: Environmental Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Behzad
authors.initials: B
authors.lastname: Shahmoradi
authors.affiliation: Environmental Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran.
authors.forename: Fardin
authors.initials: F
authors.lastname: Gharibi
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D001149:Arsenates / Q000378:metabolism*; D001151:Arsenic / Q000378:metabolism; D018053:Arsenites / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001711:Biotransformation; D060587:Groundwater / Q000382:microbiology; D007492:Iran; D011549:Pseudomonas / Q000235:genetics / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017670:Sodium Compounds / Q000378:metabolism; D014876:Water Pollution / Q000032:analysis; D062066:Water Resources
chemical_list: D001149:Arsenates; D018053:Arsenites; D012336:RNA, Ribosomal, 16S; D017670:Sodium Compounds; C017947:sodium arsenite; C009277:sodium arsenate; C015001:arsenite; D001151:Arsenic; C025657:arsenic acid
keywords: Arsenic; Bioremediation; Pseudomonas strain As-11; Water resource