The numbers of microscopic fungi isolated from soil samples after anaerobic incubation varied from tens to several hundreds of CFU per one gram of soil; a total of 30 species was found. This group is composed primarily of mitotic fungi of the ascomycete affinity belonging to the orders Hypocreales (Fusarium solani, F. oxysporum, Fusarium sp., Clonostachys grammicospora, C. rosea, Acremonium sp., Gliocladium penicilloides, Trichoderma aureoviride, T. harzianum, T. polysporum, T. viride, T. koningii, Lecanicillum lecanii, and Tolypocladium inflatum) and Eurotiales (Aspergillus terreus, A. niger, and Paecilomyces lilacimus), as well as to the phylum Zygomycota, to the order Mucorales (Actinomucor elegans, Absidia glauca, Mucor circinelloides, M. hiemalis, M. racemosus, Mucor sp., Rhizopus oryzae, Zygorrhynchus moelleri, Z. heterogamus, and Umbelopsis isabellina) and the order Mortierellales (Mortierella sp.). As much as 10–30% of the total amount of fungal mycelium remains viable for a long time (one month) under anaerobic conditions.

The micromycete complex population size and taxonomic structure is determined for sediments (bottom soils) of the White Sea; species actively functioning in the littoral zone and at depths of 10–30 m...

This review presents an analysis of the results of mycological investigations of peat obtained by the authors and other Russian and foreign scientists. High-moor peat, unlike low-moor peat, is shown to contain great reserves of fungal biomass mainly represented by mycelium. The viability of the mycelium and spores is high in the upper peat horizons and does not exceed 50% in the lower ones. In high-moor peat, fungi that are capable of destroying the complex structural polymers composing up to 50% of the peat rarely occur. The analysis of the factors limiting the activity of fungi in the high-moor peatbogs showed that, in the upper layers, the main factor was the strength of the sphagnum cellular walls. In the lower layers, the significant oxygen deficit and the accumulation of sphagnans, sphagnols, phenol-containing compounds, and antioxidants that block the activity of hydrolytic and oxidizing enzymes are of great importance.

The study of the dynamics of mycobiota during composting the cow manure and wheat straw was carried out, using DNA barcoding and cultural method. Fungi of phyla Ascomycota, Basidiomycota, Mortierellomycota, Chytridiomycota, Rozellomycota and Aphelidiomycota have been found using DNA barcoding. Cultural (plating) method identified fungi of phyla Ascomycota, Basidiomycota, Mucoromycota. All the orders of fungi determined by the plating method, with the exception of Saccharomycetales in Ascomycota and Mucorales in Mucoromycota, have been also discovered using DNA barcoding, but many other orders have been identified using the latter method. The coincidence of the species detected by both methods was very rare. The changes in the number of colony-forming and operational-taxonomic units of taxa of different levels have been observed during the transformation of manure with straw into compost. The DNA barcoding allowed to identify more fully the changes in the taxonomic and ecological-trophic structure of the fungal community during composting of manure and straw. They were manifested in a significant increase in the representation of basidiomycetes, especially Coprinus spp., Coprinellus spp., in compost, capable to transform lignin, complex organic substances of manure, and a decrease of the fraction of abundantly spore-bearing “sugars” and cellulolytic ascomycetes predominating in the initial substrates: Sordariomycetes in manure and Dothideomycetes in straw. Significant rearrangements occurred during composting in the composition of coprophilic, epiphytic, and phytopathogenic fungi. The importance of toxin-forming, allergenic, and thermophilic species of fungi that pose a danger to human health, and the possibility of assessing the readiness of compost for application to the soil as a biofertilizer, taking into account data on mycobiota, have been discussed.

A comparative assessment of the contents of total nitrogen, ammonium, nitrates, and fungal and bacterial biomasses and of the activity of nitrogen transformation in fresh casts of Aporrectodea caliginosa and in a soddy-podzolic soil was performed. The total content of nitrogen in the casts was similar to or slightly higher than that in the soil; the content of inorganic forms of nitrogen in the casts was significantly higher than in the soil. The intensities of ammonification, nitrification, and denitrification and the pool of microbial biomass with a predominance of fungi during the 1.5-week-long incubation were also significantly higher in the casts. The activity of nitrogen fixation in the casts was lower than that in the soil. In the course of the incubation, the values of these parameters in the casts became closer to those in the soil. The inhibition of fungi in the casts with cycloheximide resulted in an increasing content of inorganic nitrogen and a higher activity of denitrification. In our opinion, this phenomenon is related to the fact that limitation of the fungal growth decreases the intensity of immobilization of nitrates and the fungal competition with denitrifying bacteria for available carbon. It was supposed that the activation of the fungal growth via application of plant substrates into the soil with a high population density of earthworms could suppress the emission of gaseous nitrogen compounds. The soil processing by earthworms had a positive effect on the soil properties.

The method proposed in this study was used to isolate fungi grown under anaerobic conditions and to reveal distinctions in their abundance and species composition in different habitats. The ability of micromycetes of different taxa to grow under anaerobic conditions and ensure alcohol fermentation was determined for a representative sample (344 strains belonging to more than 60 species). The group of fungi growing under anaerobic conditions included species with high, moderate, and low fermentation activity. The ability for anaerobic growth and fermentation depended on the taxonomic affiliation of fungi. In some cases, the expression of these characteristics depended on the habitat from which the strain was isolated. The maximum level of ethanol accumulation in culture liquid (1.2–4.7%) was detected for Absidia spinosa, Aspergillus sp. of group flavus, Aspergillus terreus, Acremonium sp., Mucor circinelloides, Mucor sp., Fusarium oxysporum, F. solani, F. sambucinum, Rhizopus arrhizus var. arrhizus, Trichoderma atroviride, and Trichoderma sp.