PSXI-22 - Study of biosorption mechanisms of movable forms of lead by soil isolates of the genus Bacillus in experiments in vitro

Abstract: The research was supported by the Ministry of Science and Higher Education in accordance with the state assignment for Ural State Mining University No. 0833-2020-0008 ‘Development and environmental and economic substantiation of the technology for reclamation of land disturbed by the mining and metallurgical complex based on reclamation materials and fertilizers of a new type’. We obtain the scientific results by using funds of the Center for the collective use of scientific equipment of the Federal Scientific Center of biological systems and agricultural technologies of RAS as well (No Ross RU.0001.21 PF59, the Unified Russian Register of Centers for Collective Use - https://www.ckp-rf.ru/ckp/77384).

The search for natural bioremediators to restore crop and grazing lands in conditions of the increased anthropogenic load is a relevant and promisingly significant area of research. Thus, we were tasked to assess the prospect of using the physiological and adaptive characteristics of microorganisms of the genus Bacillus as an active biosorbent of movable forms of lead from the substrate on the in vitro model.

Soil isolates of microorganisms of the genus Bacillus extracted from samples from areas with increased lead levels were used to achieve our aim. Pb(NO₃)₂ solutions in the concentration range from 1 to 0.063M were used as the factor regulating the growth. Methods used in the work were: the method of agar basins, the nephelometric method, atomic-absorption spectroscopy, and atomic force microscopy.

B. subtilis and B. cereus were isolated from soil samples. The maximum resistance to different concentrations of Pb(NO₃)₂ was revealed for B. subtilis. The presence of lead cations in the nutrient substrate significantly increased the population density to 26.0%. At the same time, the percentage of lead sorption in the initial stage of the stationary growth phase was 65.3% with the maximum localization on the surface structures of the cell membrane.