Background: Biological components of atmospheric aerosol affect the quality of atmospheric air. Long-term trends in changes of the concentrations of total protein (a universal marker of the biogenic component of atmospheric aerosol) and culturable microorganisms in the air are studied. Methods: Atmospheric air samples are taken at two locations in the south of Western Siberia and during airborne sounding of the atmosphere. Sample analysis is carried out in the laboratory using standard culture methods (culturable microorganisms) and the fluorescence method (total protein). Results: Negative trends in the average annual concentration of total protein and culturable microorganisms in the air are revealed over more than 20 years of observations. For the concentration of total protein and culturable microorganisms in the air, intra-annual dynamics is revealed. The ratio of the maximum and minimum values of these concentrations reaches an order of magnitude. The variability of concentrations does not exceed, as a rule, two times for total protein and three times for culturable microorganisms. At the same time, for the data obtained in the course of airborne sounding of the atmosphere, a high temporal stability of the vertical profiles of the studied concentrations was found. The detected biodiversity of culturable microorganisms in atmospheric air samples demonstrates a very high variability at all observation sites. Conclusions: The revealed long-term changes in the biological components of atmospheric aerosol result in a decrease in their contribution to the atmospheric air quality index.

Oil-oxidizing microorganisms have been sampled in various regions of Siberia and used in strain associations, which degrade n-alkanes of oil from various fields by 64–92% after 6 days of growth in a wide temperature range. These strains are salt-tolerant and psychrotolerant. They are compatible with aboriginal soil microflora. Promising results have been obtained in experiments on growing plants on oil-polluted soil purified with a biodegrader of this series.

Atmospheric sounding using the Tu-134 Optik aircraft-laboratory was conducted in September 2020 over the seas of the Russian sector of the Arctic Ocean, namely the Barents, Kara, Laptev, East Siberian, Chukchi and Bering seas. Unique samples of atmospheric aerosols at altitudes from 200 and up to 10,000 m were taken, including samples for the identification of cultivated microorganisms and their genetic analysis. Data on the concentration and diversity of bacteria and fungi isolated from 24 samples of atmospheric aerosols are presented; the main phenotypic and genomic characteristics were obtained for 152 bacterial cultures; and taxonomic belonging was determined. The concentration of cultured microorganisms detected in aerosols of different locations was similar, averaging 5.5 × 10³ CFU/m³. No dependence of the number of isolated microorganisms on the height and location of aerosol sampling was observed. The presence of pathogenic and condto shitionally pathogenic bacteria, including those referred to in the genera Staphylococcus, Kocuria, Rothia, Comamonas, Brevundimonas, Acinetobacter, and others, as well as fungi represented by the widely spread genera Aureobasidium, Aspergillus, Alternaria, Penicillium, capable of causing infectious and allergic diseases were present in most analyzed samples. Obtained data reveal the necessity of systematic studies of atmospheric microbiota composition to combat emerging population diseases.

Microorganisms of atmospheric aerosols sampled at four sites with different anthropogenic load in Novosibirsk in the period from September 2020 to December 2021 are studied. Atmospheric aerosols were sampled monthly by atmospheric air filtration on reinforced Teflon membranes Sartorius for 12 h, with two-week lags. Under those sampling conditions, spore-forming bacteria of the genus Bacillus and cocci of the genera Staphylococcus and Micrococcus predominated among the cultured bacteria in winter. In the spring–summer and autumn samples of atmospheric aerosols, the concentrations and diversity of coccal forms, spore-forming and non-spore-forming bacteria, actinomycetes, and fungi sharply increased. We have identified a significant number of hemolytic spore-forming bacteria and staphylococci, which are multiresistant to antibiotics and have enzymes contributing to the development of an infectious process.

Strains of rod-shaped, facultatively anaerobic, spore-forming bacteria exhibiting negative Gram reaction were revealed after inoculation of soil, water, and silt samples from springs of the Valley of Geysers (Kamchatka) onto complete media at pH 5.0, 7,0, and 9.0 and cultivation at 28–30°C. The bacterial isolates differed in their phenotypic characteristics and in the G + C content of genomic DNA, which ranged from 41.1 to 53 mol %. The analysis of 16S rRNA gene nucleotide sequences of all isolated strains (GenBank EU497635-EU497641) revealed their close homologues among the known species of the genus Paenibacillus. At the same time, all the studied bacilli (Dg-824, Dg-904, Dg-1009, Gi-662, Gi-724, K-58, etc.) differed significantly from the nearest phylogenetic neighbors in their phenotypic characteristics, including the Gram reaction, the DNA G + C content, and a number of other determinative characteristics; therefore, they could not be assigned to previously known species.