The aim was to study bioleaching of rare earth elements from red mud by a chemoorganotrophic microorganism, and to investigate the microbe-mineral interactions. Red mud is a promising resource for scandium, whose concentration was 92 and 54 mg/kg in two samples from Germany and India, respectively; however, both showed appreciably high concentration of zirconium. A gluconic acid-producing bacterium, Gluconobacter oxydans (DSMZ 46616), was used in the bioleaching experiments under parametric variation of inoculum concentration, pulp density, and culture adaptation. At a solid load of 10% (w/v) red mud with 10% (v/v) bacterial inoculum at 37 °C, a maximum solubilisation of 83% and 94% Sc was observed after 18–20 d of incubation for Indian and German red mud, respectively. The total amount of gluconic acid excreted by the bacteria increased with an increase in pulp density up to 10% (w/v). After bioleaching, SEM-EDAX analysis of the solid residue depicted enrichment of zirconium associated with the silicate matrix, and the bacterial cells were adhered to the major mineral matrix.

目的是研究化学有机营养微生物从赤泥中生物浸出稀土元素，并研究微生物与矿物之间的相互作用。赤泥是for的一种有前途的资源，在两个来自德国和印度的样品中，mud的浓度分别为92和54 mg / kg。然而，两者均显示出相当高的锆浓度。在接种浓度，果肉密度和培养适应性的参数变化下，一种产葡萄糖酸的细菌，氧化葡糖杆菌（DSMZ 46616）被用于生物浸出实验中。固含量为10％（w / v）的赤泥和10％（v/ v）在37°C的细菌接种液中，分别在印度和德国赤泥培养18–20 d后观察到最大溶解度分别为83％和94％Sc。细菌排出的葡萄糖酸总量随着果肉密度的增加而增加，最高可达10％（w / v）。生物浸出后，固体残留物的SEM-EDAX分析表明与硅酸盐基质相关的锆的富集，细菌细胞粘附在主要的矿物基质上。