Clay minerals are very common in nature and highly reactive minerals which are typical products of the weathering of the most abundant silicate minerals on the planet. Over recent decades there has been growing appreciation that the prime involvement of clay minerals in the geochemical cycling of elements and pedosphere genesis should take into account the biogeochemical activity of microorganisms. Microbial intimate interaction with clay minerals, that has taken place on Earth’s surface in a geological time-scale, represents a complex co-evolving system which is challenging to comprehend because of fragmented information and requires coordinated efforts from both clay scientists and microbiologists. This review covers some important aspects of the interactions of clay minerals with microorganisms at the different levels of complexity, starting from organic molecules, individual and aggregated microbial cells, fungal and bacterial symbioses with photosynthetic organisms, pedosphere, up to environmental and biotechnological implications. The review attempts to systematize our current general understanding of the processes of biogeochemical transformation of clay minerals by microorganisms. This paper also highlights some microbiological and biotechnological perspectives of the practical application of clay minerals–microbes interactions not only in microbial bioremediation and biodegradation of pollutants but also in areas related to agronomy and human and animal health.

The present study investigated the influence of different nanomaterials on physiological and biochemical activity of the nitrogen-fixing bacteria Azotobacter vinelandii IMV V-7076 and phosphate mobilizing bacteria Bacillus subtilis IMV V-7023 for the development of high-efficient free-flowing bacterial complex for crop production. Among the studied nanomaterials, vermiculite stimulated the most effectively bacterial growth, synthesis of amino acids and phytohormones, dehydrogenase, catalase and peroxidase activities. Based on vermiculite and highly efficient strains of bacteria Azotobacter vinelandii IMV V-7076 and Bacillus subtilis IMV V-7023, a free-flowing bacterial complex preparation for crop production was created. The preparation was stable during storage, it improved the nitrogenous and phosphorus nutrition of plants stimulated their growth by biologically active substances and protected plants from lesion by phytopathogenic micromicetes and bacteria.

It was found that if introduced into a nutrient medium of 0.05–1 g/L nano-SiO2, the oxidant activity (OA) of the culture medium (CM) of bacilli increased by 43.2–60.1 % and the antioxidant activity (AA) decreased by 4.5–11.8 %. SiO2 nanoparticles had different effects on antiradical activity (ARA) of the CM of Bacillus subtilis IMV B-7023. In particular, nano-SiO2 had no significant effect on the ability of the CM of bacilli to inactivate the 2.2-diphenyl-1-picrylhydrazyl (DPPH·) free radical. However, for the content of the nanomaterial of 0.01–1 g/L decreased hydroxyl radical scavenging in the CM of B. subtilis IMV B-7023 on 7.2–17.6 % compared with a control. Low doses of silica nanoparticles stimulated the reducing power of the CM of bacteria and then highly suppressed it.

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The work was aimed at studying the phytochemicals available in D. antarctica plants from various sites on Antarctic Islands, introducing the plants into in vitro culture and comparing the extracts from the plants grown in situ and in vitro. All the extracts were found to contain high amount of phenols, with luteolin and hydroxybenzoic acids derivatives being the main phytochemicals in the extracts from the plants grown in situ and in vitro. Being diluted by 10 times, the extracts scavenged 50÷90% of DPPH• radicals, 20÷40% of NO• radicals and 40÷60% of OH• radicals. Despite the differences in composition, extracts from the plants grown in situ and in vitro showed similar radical scavenging activity.

The work was aimed at preparing the CA+A300 composite consisting of caffeic acid (CA) and fumed silica (A300) and at comparing the properties of CA in the solution and in the composite. The results showed that the solution and the composite are effective antioxidant/antimicrobial agents and that inclusion of CA in the CA+A300 composite provides its gradual release into solutions and reaction mixtures, thus ensuring a prolonged action of the compound.