title: Biosorption of heavy metals by lactic acid bacteria and identification of mercury binding protein.
abstract: Heavy metals cause various health hazards. Using lactic acid bacteria (LAB), we tested the biosorption of heavy metals e.g. cadmium (Cd) (II), lead (Pb) (II), arsenic (As) (III), and mercury (Hg) (II). Cd (II) sorption was tested in 103 strains using atomic absorption spectrophotometery (AAS). Weissella viridescens MYU 205 (1 × 10(8) cells/ml) decreased Cd (II) levels in citrate buffer (pH 6.0) from one ppm to 0.459 ± 0.016 ppm, corresponding to 10.46 μg of Cd (II). After screening, 11 LAB strains were tested using various pH (pH 4.0, 5.0, 6.0, 7.0) showing the sorption was acid sensitive; and was cell concentration dependent, where the Cd (II) concentration decreased from one ppm to 0.042 (max)/0.255 (min) ppm at 1 × 10(10) cells/ml. Additionally, the biosorption of Pb (II), As (III), and Hg (II) were tested using an inductively coupled plasma mass spectrometer (ICP-MS). The Hg (II) concentration was reduced the most followed by Pb (II) and As (III). Many of the bacterial cell surface proteins of W. viridescens MYU 205 showed binding to Hg (II) using the Hg (II) column assay. Having a CXXC motif, a ∼14 kDa protein may be one of the Hg (II) binding proteins. LAB biosorption may aid the detoxification of people exposed to heavy metals.
authors.affiliation: School of Food, Agricultural and Environmental Sciences, Miyagi University, 2-2-1, Hatatate, Taihaku-ku, Sendai, Miyagi 982-0215, Japan. kinoshih@myu.ac.jp
authors.forename: Hideki
authors.initials: H
authors.lastname: Kinoshita
authors.forename: Yui
authors.initials: Y
authors.lastname: Sohma
authors.forename: Fumika
authors.initials: F
authors.lastname: Ohtake
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Ishida
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawai
authors.forename: Haruki
authors.initials: H
authors.lastname: Kitazawa
authors.forename: Tadao
authors.initials: T
authors.lastname: Saito
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kimura
mesh_terms: D000818:Animals; D001151:Arsenic / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D006801:Humans; D007422:Intestines / Q000382:microbiology; D056546:Lactobacillales / Q000302:isolation & purification / Q000378:metabolism*; D007854:Lead / Q000378:metabolism*; D008628:Mercury / Q000378:metabolism*; D013552:Swine; D014675:Vegetables / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D002104:Cadmium; D007854:Lead; D008628:Mercury; D001151:Arsenic
keywords: Biosorption; Cadmium; Detoxification; Heavy metal; Lactic acid bacteria; Mercury