title: Cobalt separation by Alphaproteobacterium MTB-KTN90: magnetotactic bacteria in bioremediation.
abstract: Bioremediation of toxic metals by magnetotactic bacteria and magnetic separation of metal-loaded magnetotactic bacteria are of great interest. This bioprocess technique is rapid, efficient, economical, and environmentally friendly. In this study, cobalt removal potential of a novel isolated magnetotactic bacterium (Alphaproteobacterium MTB-KTN90) as a new biosorbent was investigated. The effects of various environmental parameters in the cobalt removal and the technique of magnetic separation of cobalt-loaded bacterial cells were studied. Cobalt removal by MTB-KTN90 was very sensitive to pH solution; higher biosorption capacity was observed around pH 6.5-7.0. When biomass concentration increased from 0.009 to 0.09 g/l, the biosorption efficiency increased from 13.87 % to 19.22 %. The sorption of cobalt by MTB-KTN90 was rapid during the first 15 min (859.17 mg/g dry weight). With the increasing of cobalt concentrations from 1 to 225 mg/l, the specific cobalt uptake increased. Maximum cobalt removal (1160.51 ± 15.42 mg/g dry weight) took place at optimum conditions; pH 7.0 with initial cobalt concentration of 115 mg/l at 60 min by 0.015 g/l of dry biomass. The results showed maximum values for constants of Langmuir and Freundlich models so far. The biosorption mechanisms were studied with FTIR, PIXE, and FESEM analysis. Cobalt-loaded MTB-KTN90 had ability to separate from solution by a simple magnetic separator. Magnetic response in MTB-KTN90 is due to the presence of unique intracellular magnetic nanoparticles (magnetosomes). The orientation magnetic separation results indicated that 88.55 % of cobalt was removed from solution. Consequently, Alphaproteobacterium MTB-KTN90 as a new biosorbent opens up good opportunities for the magnetic removal of cobalt from the polluted aquatic environments.
authors: Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, Iran. parisa_tajer@yahoo.com.|Department of Microbiology, Faculty of Biological Science, Alzahra University, Tehran, Iran. parisa_tajer@yahoo.com.
authors: Parisa
authors: P
authors: Tajer-Mohammad-Ghazvini
authors: Department of Microbiology, Faculty of Biological Science, Alzahra University, Tehran, Iran. rkasra@yahoo.com.
authors: Rouha
authors: R
authors: Kasra-Kermanshahi
authors: Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
authors: Ahmad
authors: A
authors: Nozad-Golikand
authors: Department of Genetics, Faculty of Biological Science, Tarbiat Modares University, Tehran, Iran.
authors: Majid
authors: M
authors: Sadeghizadeh
authors: Nuclear Science and Technology Research Institute, Tehran, Iran.
authors: Saeid
authors: S
authors: Ghorbanzadeh-Mashkani
authors: Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
authors: Reza
authors: R
authors: Dabbagh
mesh_terms: D020561:Alphaproteobacteria / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003035:Cobalt / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D003035:Cobalt
keywords: Biosorption; Magnetic nanoparticles; Magnetotactic bacteria; Microbial clean-up; Nanobiotechnology