Keratinolytic fungi representing the genus Arthroderma that were isolated from the soils of a rook (Corvus frugilegus) colony were used as biological agents for the disposal of waste feathers. The aim of this study was to assess the abilities of Arthroderma tuberculatum and Arthroderma multifidum fungi with a varied inflow of keratin matter to biodegrade waste feathers. The evaluation was based on the determination of feather mass loss, the activity of keratinolytic enzymes, and the content of mineral N and S forms. It was found that the activity of protease released by the fungi contributed to an increase in the level of soluble proteins and peptides and the concentration of ammonium ions, as well as alkalization of the culture medium. Keratinase activity was significantly correlated with sulfate release, especially in A. tuberculatum cultures. The strains of A. tuberculatum fungi isolated from the soil with the highest supply of organic matter, i.e., strains III, IV, and V, had the lowest enzymatic activity, compared to the A. multifidum strains, but they released mineral nitrogen and sulfur forms that are highly important for fertilization, as well as nutritionally important peptides and amino acids. A. tuberculatum strains can be used for the management of waste feathers that can be applied in agricultural practice.

Fungi that decompose keratinized animal remains are an important component of the arable soil microbiome. The aim of the study is to characterize the communities of keratinophilic and co-inhabiting (non-keratinophilic) fungi in four cultivated soils that differ in physico-chemical properties, with particular emphasis on granulometric fractions, which have so far been omitted from studies concerning the ecology of these micromycetes. Fungi were isolated using the keratin-baiting method. Fungal species identification was carried out on the basis of their macro- and micromorphological features. The Simpson diversity index and Marczewski–Steinhaus similarity index were calculated for precise determination of the relationships between fungal communities. In the studied soils, Trichophyton ajelloi and Ctenomyces serratus dominated among keratinophilic fungi, while Purpureocillium lilacinum and Metacordyceps chlamydosporia, from the orders Eurotiales and Hypocreales, were dominant among non-keratinophilic fungi. The frequency of keratinophilic fungi was significantly positively correlated with pH and the content of two granulometric fractions, as opposed to non-keratinophilic fungi. This was reflected in the higher growth rates of keratinomycetes in loamy soil, chernozem, and rendzina, i.e., soils with a higher content of silt and clay fractions compared to sandy soil characterized by a high content of sand fractions. The species composition of both groups of fungi was most similar between loamy soil and chernozem, whereas the greatest differences were found for sandy soil and rendzina. Chernozem was characterized by the highest diversity of fungal species from both groups of fungi. The study, in addition to providing information about ecological factors, provided a collection of keratinomycete strains that can be used as a starting material for subsequent research stages regarding keratinolytic activity of these fungi and their potential use in agricultural practices.

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The aim of the study was to optimize culture conditions and medium composition to accelerate the biodegradation of chicken feather waste by keratinolytic soil strains of Trichophyton ajelloi, which are poorly known in this respect, as well as to propose hitherto unconsidered culture conditions for these fungi in order to obtain a biopreparation with a high fertilization value. Different pH of the medium, incubation temperatures, amounts of chicken feathers, additional carbon sources, and culture methods were tested. The process of optimizing keratin biodegradation was evaluated in terms of measuring the activity of keratinase, protease, disulfide reductase, concentration of released soluble proteins and peptides, total pool of amino acids, ammonium and sulfate ions, changes in medium pH, and feather weight loss. It was found that the studied fungal strains were capable of decomposing and mineralizing keratin from feather waste. Regarding the fertilizer value of the obtained hydrolysates, it was shown that the release of sulfate and ammonium ions was highest in a stationary culture containing 2% feathers with an initial pH of 4.5 and a temperature of 28 °C. Days 14–21 of the culture were indicated as the optimal culture time for these fungi to obtain biopreparations of high fertilizing value.

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