title: Resistance, bioaccumulation and solid phase extraction of uranium (VI) by Bacillus vallismortis and its UV-vis spectrophotometric determination.
abstract: Bioaccumulation, resistance and preconcentration of uranium(VI) by thermotolerant Bacillus vallismortis were investigated in details. The minimum inhibition concentration of (MIC) value of U(VI) was found as 85 mg/L and 15 mg/L in liquid and solid medium, respectively. Furthermore, the effect of various U(VI) concentrations on the growth of bacteria and bioaccumulation on B. vallismortis was examined in the liquid culture media. The growth was not significantly affected in the presence of 1.0, 2.5 and 5.0 mg/L U(VI) up to 72 h. The highest bioaccumulation value at 1 mg/L U(VI) concentration was detected at the 72nd hour (10 mg/g metal/dry bacteria), while the maximum bioaccumulation value at 5 mg/L U(VI) concentration was determined at the 48th hour (50 mg metal/dry bacteria). In addition to these, various concentration of U(VI) on α-amylase production was studied. The α-amylase activities at 0, 1, 2.5 and 5 mg/L U(VI) were found as 3313.2, 3845.2, 3687.1 and 3060.8 U/mg, respectively at 48th. Besides, uranium (VI) ions were preconcentrated with immobilized B. vallismortis onto multiwalled carbon nanotube (MWCNT) and were determined by UV-vis spectrophotometry. The surface macro structure and functionalities of B. vallismortis immobilized onto multiwalled carbon nanotube with and without U(VI) were examined by FT-IR and SEM. The optimum pH and flow rate for the biosorption of U(VI) were 4.0-5.0 and 1.0 mL/min, respectively. The quantitative elution occurred with 5.0 mL of 1 mol/L HCl. The loading capacity of immobilized B. vallismortis was determined as 23.6 mg/g. The certified reference sample was employed for the validation of developed solid phase extraction method. The new validated method was applied to the determination of U(VI) in water samples from Van Lake-Turkey.
authors.affiliation: Department of Food Processing, Technical Science Vocational School, Mersin University, TR-33343, Yenisehir, Mersin, Turkey. Electronic address: sadin77@hotmail.com.
authors.forename: Sadin
authors.initials: S
authors.lastname: Ozdemir
authors.affiliation: Department of Biology, Faculty of Art and Science, Siirt University, 56100, Siirt, Turkey.
authors.forename: M Kadir
authors.initials: MK
authors.lastname: Oduncu
authors.affiliation: Health Services Vocational High School, Medical Marketing and Promotion Programme, Mardin Artuklu University, 47200, Mardin, Turkey.
authors.forename: Ersin
authors.initials: E
authors.lastname: Kilinc
authors.affiliation: Department of Chemistry, Faculty of Science, Erciyes University, 38039, Kayseri, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Soylak
mesh_terms: D001407:Bacillus / Q000378:metabolism*; D037742:Nanotubes, Carbon / Q000382:microbiology; D011834:Radiation Monitoring / Q000379:methods*; D052616:Solid Phase Extraction; D014501:Uranium / Q000378:metabolism*; D014875:Water Pollutants, Radioactive / Q000032:analysis
chemical_list: D037742:Nanotubes, Carbon; D014875:Water Pollutants, Radioactive; D014501:Uranium
keywords: Bacillus vallismortis; Bioaccumulation; Preconcentration; Resistance; U(VI)