L. A. Ulakhanova, S. V. Gomboeva, V. Zh. Tsyrenov

Abstract

Silicate bacteria have a wide biotechnological potential, they produce a large number of biologically active substances: enzymes that destroy silicates; fungicidal and antimicrobial compounds; phytohormones and exopolysaccharides (EPS). At the same time, they are able to use silicon-containing minerals as a source of additional energy. The literature provides studies on the destruction of polysilicon compounds by silicate bacteria of the speciessilicate bacteria. They are capable of destroying quartz, aluminosilicates with the release of Si, K and other elements. There is also information about stimulating the reproduction of silicate bacteria when growing on mineral media with the addition of silicon-containing components. At the same time, the influence of polysilicon compounds on the synthesis of exopolysaccharides by silicate bacteria is not considered. The exoglycans released by them are used in various industries: mining, oil production, pharmaceutical, food and cosmetic. The studies used isolated pure cultures of silicate bacteria, the biosynthetic activity of which was compared with strains of Paenibacillus mucilaginosus B7519 and B4901 (VKPM, GosNIIgenetics). Bacteria were isolated from the soils and sand of the Baikal region. The influence of silicon-containing components (bentonite, quartz sand) of the nutrient medium on crop growth and EPS synthesis was investigated. The positive effect of silicate minerals on the growth of isolated strains and museum cultures of P. mucilaginosus has been confirmed. Strain B-4901 had the highest amount of CFU/ml on nutrient media with both quartz sand and bentonite. The influence of siliconcontaining components on the EPS yield of the studied microorganisms has been established. The highest EPS yield was observed in the VSGUTU-2 strain on a nutrient medium with the addition of quartz sand, and the B7519 strain had the best synthesis on a medium with the addition of bentonite. The VSGUTU-1 strain showed the same yield of exopolysaccharides on two variants of media with silicon-containing components, whereas the amount of EPS in the B4901 strain did not increase with the addition of bentonite and quartz sand. The lowest EPS yields were on nutrient media without the addition of a silicon source.