The use of inoculum containing autochthonous compost microorganisms Bacillus subtilis, B. amyloliquefaciens, Pseudomonas aeruginosa allowed to enhance biodegradation of food waste during composting. The survival of the introduced microorganisms was verified by classical microbiological and molecular biological methods. The introduction extended the high-temperature stage by 4 days, prevented acidification of the medium, increased organic matter degradation and moisture evaporation, resulting in a 51% reduction in waste weight in two weeks. Introduced P. aeruginosa appeared to play a key role in the initial stage and was not detected after increasing the temperature to 60C.

Increasing plastic pollution is a serious environmental problem as widespread production and inadequate disposal of plastic materials lead to adverse impacts on ecosystems. The structural and functional characteristics of the anaerobic microbial community contacting with extruded polystyrene (XPS) waste were investigated under methanogenic (MG) and nitrate-(NR) and sulfate-reducing (SR) conditions. The presence of XPS in the microbial community was shown to have no negative effect on the processes of biogas formation and, on the contrary, resulted in an increase in the yield of methane and volatile fatty acids and a change in their ratio. Microparticles of different sizes were found in the culture liquid of the variants with XPS: 2.4 × 106/mL (NR), 1.2 × 106/mL (SR), and 0.4 × 106/mL (MG), while no microparticles were found in the control variants. Scanning electron microscopy revealed that in all experimental variants the surface of the polymer became looser, more textured, with formation of irregularities, cracks, and holes. Increased diversity in the microbial community associated with an increase in the number of microbial morphotypes, correlated with the results of high-throughput sequencing of the 16S rRNA gene. When XPS was introduced into an anaerobic community incubated in different donor-acceptor conditions, the number of microbial groups in it increased, as well as the proportion of hydrolytic and acidogenic bacteria (Sedimentibacter, Lentimicrobium), acetogenic syntrophs (Syntrophomonas, Desulfovibrio, Geobacter), and methanogenic archaea (Methanosarcina, Methanobacterium). Our study showed that the XPS waste was not inert for the microbial community, the contact with it resulting in significant changes in its structure and functioning. Changes in the sample surface, emergence of microparticles, and differences in the composition of the intermediate and terminal metabolic products may indicate slow partial degradation of the plastic via fragmentation. However, since the experiments were carried out using household XPS containing various fillers apart from the main polymer, it is probable that, along with polystyrene, additional substances included in its composition (plasticizers, dyes, etc.) are also subject to degradation. The ability of microorganisms to degrade the polymer itself requires further research.

The extracellular proteinase–activator of human plasma prekallikrein was isolated from the culture fluid of the micromycete A. terreus 2, and its physicochemical, kinetic, and biochemical properties were studied. It has been established that the A. terreus 2 extracellular proteinase is a glycosylated serine proteinase with an isoelectric point of 4.6, a molecular weight of about 37 kDa, and optimum activity at pH 10.0 and a temperature of 37°C. In a number of its properties this proteinase is similar to the proteinase–activator of protein C, which is produced by the micromycete A. ochraceus L-1.

Azo dyes are soluble xenobiotics stable under oxidizing conditions, which are widely used in human practice; they are present in liquid and solid industrial and household wastes and regularly enter the environment. In this work, we investigated the possibility of degradation of the technical azo dye Methyl Red (MR) by anaerobic microbial communities isolated from the Volga River sediments, and MR effect on community composition and methanogenic activity. This is the first report on ability of such azo dye-unadopted communities to degrade MR with production of stable N , N -dimethyl- p -phenylenediamine and biodegradable 2-aminobenzoic acid. Comparison of methanogenesis rates in communities with and without MR revealed a decrease in biogas production by 43.80% due to the toxic effect of MR (and, possibly, of aromatic intermediates of its decomposition) on microorganisms. Next-generation sequencing of the 16S rRNA gene revealed significant changes in the structural and functional organization of the methanogenic community in the presence of MR and a shift among the dominant groups. In the community with MR the share of bacteria of the family Geobacteriaceae increased almost 5-fold, while that of the family Clostridiaceae decreased 3‑fold, and the genus Proteiniclasticum became dominant. In the presence of MR, representatives of the families Methanobacteriaceae , Methanofastidiosaceae , Methanoregulaceae , Methanosaetaceae , and Methanomassillicoccaceae , which constituted 33.32% of the total number of archaea in the initial community, were not detected. An increase in the proportion of microorganisms of the families Desulfоvibrionaceae , Desulfosarcinaceae , and Gallionellaceae was presumably related to their possible involvement in MR degradation, since they usually act as syntrophs in methanogenic communities. MR decolorization was confirmed to require the presence of living cells, adsorption being only its initial stage, and the effect of chemical reduction of the azo bond was minimal. Our preliminary laboratory model shows that while natural communities are potentially capable of destroying MR, the azo dye also has a significant effect on their structure.

A preparation of thrombolytic enzymes of micromycete S. strictum 203 was obtained and characterized. The expressed urokinase activity of producer proteinases was determined, and the content of the complex of three alkaline trypsin-like thiol-dependent serine-type proteinases with different isoelectric points (4.5, 7.2 and 11.8) but close molecular weight was detected in the enzyme preparation (about 35 kDa). One of the proteinases (proteinase III) was not glycosylated, and the rest were glycoproteins. The proteinases differed in the spectrum of proteolytic activity in relation to proteins; the thrombus components also turned out to be different. Presumably, the enzymatic urokinase activity causes proteinases to activate plasminogen.

— The growing worldwide production of synthetic plastics leads to increased amounts of plastic pollution. Even though microbial degradation of plastics is known to be a very slow process, this capacity has been found in many bacteria, including invertebrate symbionts, and microscopic fungi. Research in this field has been mostly focused on microbial degradation of polyethylene, polystyrene, and polyethylene terephthalate (PET). Quite an arsenal of different methods is available today for detecting processes of plastic degradation and measuring their rates. Given the lack of generally accepted protocols, it is difficult to compare results presented by different authors. PET degradation by recombinant hydrolases from thermophilic actinobacteria happens to be the most efficient among the currently known plastic degradation processes. Various approaches to accelerating microbial plastic degradation are also discussed.

The effect of nitrogen sources in the fermentation medium and the cultivation conditions on the production of proteinases with plasmin-like and prekallikrein activation activity by micromycete Aspergillus terreus 2 was investigated. The highest secretion of proteinases was achieved when the micromycete was cultivated on a medium containing both amine- and mineral nitrogen sources at an initial pH of 5.5 and at 28°С. It was established that the extracellular micromycete proteinases are equally capable of hydrolyzing fibrin and fibrinogen.

It has been shown that micromycetes Aspergillus ustus 1 and Tolypocladium inflatum k1 secrete proteolytic enzymes that possess high collagenolytic, fibrinolytic, and elastolytic activity. The activity of proteinases hydrolyzing fibrillar proteins, which was determined by the cleavage of azo-collagen, was 122.6 × 10–3EAzc/mL in A. ustus 1 and 69.7 × 10–3EAzc/mL in T. inflatum k1 (EAzc is the amount of azocollagen cleaved in 1 min (μg). The maximum values of activity were observed during submerged cultivation of A. ustus 1 for 4 days and of T. inflatum k1 for 5 days. It has been shown that the maximum of collagenolytic and general proteolytic activity during the cultivation of A. ustus 1 are time-separated, unlike T. inflatum k1, which, presumably, can simplify the procedure for obtaining proteinases active against fibrillar proteins.

By combining DGGE-PCR method, classical microbiological analysis and light-and electron microscopic observations, it was found that the composition of microbial communities of central Russia regions kefir grains, starter and kefir drink include bacteria of the genera Lactobacillus, Leuconostoc and Lactococcus, and yeast anamorphs of the genera Saccharomyces, Kazachstania and Gibellulopsis. Fifteen prokaryotic and four eukaryotic pure cultures of microorganisms were isolated and identified from kefir grains. It has been shown that members of the genus Lactobacillus prevailed in kefir grains, whereas strains Leuconostoc pseudomesenteroides and Lactococcus lactis dominated in the final product - kefir drink. Yeasts contained in kefir grains in small amounts have reached a significant number of cells in the process of development of this dairy product. The possibility of reverse cell aggregation has been attempted in a mixed cultivation of all isolated pure cultures, but full formation kefir grains is not yet observed after 1.5 years of observation and reinoculations.

Differences in the action of extracellular proteases from Aspergillus ochraceus and Aspergillus terreus on proteins of plasma hemostasis which is responsible for the activation initiation of proteins of the prothrombin complex have been revealed. It has been found that proteases produced by A. ochraceus have a direct influence on protein C and factor X while the exoprotease from A. terreus causes their activation indirectly via stimulation of the kallikrein system. The ability of extracellular proteases of micromycetes to activate prekallikrein in human blood plasma has been demonstrated for the first time by the example of A. terreus .

Survival of bacterial populations treated with lethal doses of antibiotics is ensured by very small numbers of persister cells. Unlike antibiotic-resistant cells, antibiotic tolerance of persisters is not inheritable and reversible. The present work provides evidence supporting the hypothesis on transformation (maturation) of persisters of an opportunistic pathogen Pseudomonas aeruginosa, revealed by ciprofloxacin (CF) treatment (25–100 μg/mL), into dormant cystlike cells (CLC) and nonculturable cells (NC), as was described previously for a number of non-spore-forming bacteria. Subpopulations of type 1 and type 2 persisters, which survived antibiotic treatment and developed into dormant forms, were heterogeneous in their capacity to form colonies or microcolonies upon germination as resistance to heating at 70°C and in cell morphology. Type 1 persisters, which were formed after 1-month incubation of the stationary-phase cultures grown in the medium with decreased C and N concentrations, developed in several types of surviving cells, including those similar to CLC in cell morphology. In the course of 1-month incubation of type 2 persisters, which were formed in exponentially growing cultures, other types of surviving cells developed: immature CLC and L-forms. Unlike P. aeruginosa CLC formed in the control post-stationary phase cultures without antibiotic treatment, most of 1-month persisters, especially type 2 ones, were characterized by the loss of colony-forming capacity, probably due to transition into an nonculturable state with relatively high numbers of live intact cells (Live/Dead test). Another survival strategy of P. aeruginosa populations was ensured by a minor subpopulation of CF-tolerant and CF-resistant cells able to grow in the form of microcolonies or regular colonies of decreased size in the presence of the antibiotic. The described P. aeruginosa dormant forms may be responsible for persistent forms in bacteria carriers and latent infections and, together with antibiotic-resistant cells, are important as components of test systems to assay the efficiency of potential pharmaceuticals against resistant infections.