Biodegradation of the As-Bearing Flotation Concentrate with Silicate Bacilli

Biodegradation of mineral materials is object of great research interest. Its positive practical application is related with industrial bioleaching for microbial recovery of valuable metals from the low-grade ores and solid wastes. Its negative significance is related with biodestruction of building materials and includes both metal biocorrosion and mineral biodegradation. The most studied theme is bioleaching sulfide ores that is accompanied with the microbial sulfide oxidation. Meanwhile, biodegradation of silicates is still an insufficient studied problem. In this paper, authors present a research on possible role of the so-named “silicate bacilli” in biodegradation of the arsenopyrite gold-bearing flotation concentrate which is refractory, toxic, and contains aluminosilicates. The paper belongs both to materials science and microbiology and describes biodegradation of silicate materials, namely: (1) isolation of the silicate bacilli from the concentrate and their identification, (2) experiments on the biodegradation of the concentrate with the strains, (3) bacterial formation of micro-voids on the mineral surface, (4) study on the strain resistance to toxic mineral arsenic via genetic analyses of their genomes. In general, the work presents the first suggestions about ways of the surface biodestruction in solid aluminosilicates that realized by silicate bacteria.