Mechanisms in biomining of magnesite and its scale up production

Magnesite, that is called magnesium carbonate (MgCO3) mineral, is one of the important ores of Turkey among countries rich in terms of ore resources. Since magnesium found in magnesite is a valuable raw material at the pure state or various compound states for present-day technology, developing new approaches on obtaining and enrichment of this material are very beneficial on account of national economics. In order to trade magnesite economically, SiO2 and CaCO3 rates of raw material needs to be less than 2 percent and 1 percent, respectively. A number of different enrichment methods have been developed to increase purity of magnesite. The aim of the present study is to develop a biomining process which will be used for enrichment of magnesite from different ores in Turkey by dissolving carbonate compounds, to scale up this process and to determine Ca dissolving factors. Previously and newly isolated and identified bacterial strains, Enterococcus spp., Lactococcus spp. Staphylococcus spp., and fungi isolate Neurospora spp. were used. Optimum working parameters were identified for all microorganisms. Results indicated that, microorganisms show effective dissolving capacity at 30ºC, pH between 3 and 7, in the presence of glucose as carbon source. The subcronic toxicology tests performed with Wistar rats, showed that Enterococcus spp., and Lactococcus spp. strains are not pathogenic and toxic for mammalian. Lactococcus spp. was used at scale up studies and 3 L and 30 L fermenter processes were performed successfully. Consequently, genomic, transcriptomic and proteomic analysis of Enterococcus spp. and Lactococcus spp. strains were performed to illustrate the molecular mechanisms of magnesite biomining. This is the first study to demonstrate Enterococcus spp. and Lactococcus spp. strains can be used for enrichment of magnesite in industrial scale. A further study needs to be done to identify other microorganisms from nature that have potential to be used in magnesite biomining and formulation of them for industrial scale.