INFLUENCE OF LITHIUM-COBALT MIXTURE ON BACTERIAL OXIDATION OF FERROUS IONS BY ACIDITHIOBACILLUS FERROOXIDANS JCM 3863
VYARA MAMATARKOVA*, SILVIYA GENEVA
Department of Biotechnology, Faculty of Biology, Sofia University
“St. Kliment Ohridski”, Sofia, Bulgaria
*Corresponding author: vsavamama@yahoo.com
Keywords: Acidithiobacillus ferrooxidans; lithium, cobalt, oxidation activity
Abstract: Iron oxidizing bacteria Acidithiobacillus ferrooxidans show high resistance to heavy and toxic metals such as Zn, Cd, Hg, As, Co, Cu etc. In recent years, the investigations are directed toward the possibility of reutilization of some heavy and precious metals by bioleaching from solid wastes of lithium-ions batteries and spent electronic devices. In this research, we evaluated the dynamics of biooxidation of ferrous iron by Acidithiobacillus ferrooxidans JCM 3863 in the presence of lithium as well as of a mixture of cobalt and lithium ions. The experiments were carried out in batch cell cultures, in shake flasks at 190 pm and temperature 28±0.5ºC. The original liquid medium 9K was used. Both metal ions were added in different concentrations from 0.5 to 3.25 g/l in a ratio 1:1 in the mixture.
The dynamics of bacterial oxidation of ferrous iron in presence of Li+ and Co2+ have been investigated in comparison with this one without metal ions – biological control. The bacteria in suspended cell cultures haven’t been adapted preliminarily to increasing concentrations of metal ions. It has been found that the combination of metal ions (Li+ and Co2+) completely inhibits the oxidation process at 3.25 g/l irreversibly. Lithium Li+ ions in the range of concentration up to 3.25 g/l slow down the oxidation rate, but not inhibit bacterial activity. The results show that the bacteria Acidithiobacillus ferrooxidans JCM 3863 can be used in future investigations for bioleaching of lithium and cobalt from batteries for domestic electronic devices in the investigated range of concentrations.