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.

Magnetic Nanoparticles: From Design and Synthesis to Real World Applications

“…Simple magnetic isolation of some cells is possible due to their inherent magnetic properties—red blood cells (hemoglobin iron is in a paramagnetic state), magnetotactic bacteria, etc. [ 200 , 201 ].…”

An overview of heavy metal removal from wastewater using magnetotactic bacteria

“…heavy metal ions) from wastewater (Table ). Furthermore, isotherm and kinetic models have rarely been employed, even though they are widely acknowledged as very helpful tools for transferring technology from laboratory to practical/applied scales …”

“…The adsorption process has been used for the investigation of removal performance and mechanisms in most of the research studies because a rate‐controlling step in the adsorption presents intimation to understand removal mechanism. Thus, different types of adsorption isotherms (Langmuir, Freundlich and D‐R) and kinetic (pseudo‐first‐order, pseudo‐second‐order, Weber–Morris and Elovichand Boyd) models were used and results were compared using linear regression correlation coefficient ( R ) values . The literature showed that a pseudo‐second‐order kinetic model and Langmuir isotherm were the best fit with adsorption kinetic and isotherm data in most of the reports (Table ).…”

“…Nevertheless, MTB have a proven superior capacity for biosorption for heavy metals [e.g. Au(III), Cu(II), Pu, Cobalt, Cr(VI) and Ag (I)] . The presence of functional groups (e.g.…”

Magnetotactic bacteria used to generate electricity based on Faraday's law of electromagnetic induction

“…) and bioremediation of cobalt (Tajer‐Mohammad‐Ghazvini et al . ). Lastly, it has been shown that magnetosomes can immobilize enzyme activity such as uricase and glucose oxidase.…”