Fungi of the Pleurotus genus , are known for their health-promoting properties. They are grown on a wide range of lignocellulosic substrates , including i.e. straw , rice hulls and corn residues. There are numerous literature reports proving that the composition of the culture substrate affects the growth rate and yield of oyster mushrooms. The aim of the present study was to optimize the mixture of the culture medium , composed of agro-industrial waste , for the cultivation of Pleurotus ostreatus in order to achieve maximum yield and the fastest mycelial growth. In addition , the chemical composition of selected wastes was determined and the possibility of using spent P. ostreatus substrate as a biostimulant for plant growth was assessed. The best results in terms of yield , mycelial growth rate , and time required for substrate colonization , primordia formation , and first harvest , were obtained for straw with spent brewery grains and for straw with wheat bran in a proportion of 70/30% , while the mixture of wheat straw , wheat bran and sugar beet pulp in a proportion of 50/25/25% gave slightly poorer results. The maximum yield of 51.7 g/bag and the fastest growth was obtained for the substrate with the addition of spent brewery grains. Substrate formula 70% wheat straw , with 30% addition of spent brewery grains , gave the fastest time for substrate colonization , primordia formation and the first harvest (16 days , 20 days , 28 days respectively). The study carried out by ICP-Spectrometry technique confirmed that the Pleurotus spent substrate is a source of valuable elements (Ca , Cu , Fe , K , P , Mg , Mn , S) , indicating its biostimulatory potential in agriculture. Enzyme activity associated with substrate (carbohydrate) degradation , performed using a commercial API ZYM assay increased significantly in straw with spent brewery grains and straw with wheat bran mixture. The highest total levels of degradation products were examined by photometric method using commercially available Hach Lange cuvette tests. The highest total content of Pleurotus substrate degradation products , including organic acids , orthophosphate , ammonia nitrogen , nitrate , and nitrite , was found in the substrate supplemented with brewery grains. Their levels increased significantly compared to the control , indicating enhanced degradation activity in this substrate. Substrate after cultivation of higher fungi (Spent Mushroom Substrate-SMS) contains large amounts of valuable elements and can affect the growth and yield of crops. Their amount varies depending on the substrate used and depends on the availability of sources of C and N. Studies of the growth rate of P. ostreatus on a wide range of lignocellulosic substrates , i.e. straw , corn residues , rice husks , among others , are known. The authors of the present study extended these studies to evaluate the biodegradation of waste materials that have not yet been used in the culture of higher fungi (brewery spent grain , wheat bran , beet pulp) , making a significant contribution to the discipline. This study supports the implementation of the Sustainable Development Goals , by promoting the valorization of agro-industrial waste through sustainable biotechnological processes.

The yeast strain Yarrowia lipolytica IPS 21 was tested for its ability to degrade potentially toxic chrome-tanned leather shavings (CTLS) in a liquid environment. Biological and chemical parameters were monitored during a 48-h period of biotransformation of the protein-rich waste. CTLS was added at a concentration of 0.1–4% (wt/wt) to a modified YPG medium (15 g L ⁻¹ yeast extract and 5 g L ⁻¹ NaCl). Biodegradation and bioconversion were performed in a one-step process. It was found that the higher degradation rate depended on the activity of the proteases and the pH of the medium, but not on the initial inoculum ratio and the activity of the dehydrogenase. The highest efficiency of the process was obtained for 4% (wt/wt) CTLS on day 2 (degradation rate 58–67%, biomass production 2.11–2.20 g L ⁻¹ , protease activity 312 U mg ⁻¹ protein, and pH 9.20). Our results showed that total chromium was probably not transported across the cytoplasmic membrane of Y. lipolytica IPS21 and that chromium (III) was not oxidized to chromium (VI). The phytotoxicity of selected amino acid supernatants [2.5% (vol/vol)] was tested after the bioconversion process. It was found that the supernatants had a stimulating effect on the plants tested. The root elongation was 29–28% higher than that of the reference samples. This result makes Y. lipolytica IPS21 a potential candidate for safely converting potentially toxic protein-rich wastes into valuable products without enzyme isolation, e.g., amino acid fertilizers. IMPORTANCE: Enzyme technologies have the greatest practical relevance to environmental trends. Overcoming the barrier of the high cost of carbon substrates used for biotransformation is the main challenge of these methods. The huge potential of the use of extracellular proteases of Yarrowia species or amino acids in various industries indicates the need for the extension of basic research on waste as a carbon source for this yeast. The experiments demonstrated that it is possible to use Y. lipolytica IPS21 for bioconversion of chrome-tanned leather shavings (CTLS) in a single-step process and to produce high-value amino acid supernatant without having an isolated enzyme. In our study, we show the effect of 2.5% (vol/vol) CTLS supernatant obtained from Y. lipolytica IPS21 on the elongation of the root system of selected plants and provide information on the effect of environmental factors on the efficiency of the bioconversion and the migration of chromium.

The aim of this study was to examine the effects of foliar application of protein biostimulants in combination with extracts from field horsetail (E. arvense L.), common tansy (T. vulgare L.), or yarrow (A. millefolium L.) on winter wheat. Initially, the fungistatic activity and phytotoxicity of three extract concentrations (1%, 5%, 10%) were tested on reference plants. The average results indicated a decrease in root elongation stimulation with increasing concentrations of all extracts. Antimicrobial tests revealed that the 5% and 10% extracts exhibited the strongest activity, especially against S. griseus, whereas the 1% extracts showed no inhibitory effect. The 5% concentration was chosen as optimal due to its comparable efficacy to a reference fungicide. Subsequently, the impact of combining foliar application of extracts with protein biostimulants on wheat seedling and root length, chlorophyll fluorescence, photosynthetic pigments, and soil dehydrogenase activity was analyzed. Horsetail and yarrow extracts combined with biostimulants improved plant growth, depending on dose and combination. This was particularly evident for variants S5-B8, K5-B4, K5-B8, A-B8, for which seedling lengths were 23.6 cm (16.8%), 24.4 cm (20.8%), 23.9 cm (18.3%), and 23.6 cm (16.8%), respectively. The maximum increase in chlorophyll (a + b) content (38.30%, 35.81%, and 41.24%) occurred in plants treated with S5-B4, K5-B8, and A-B4, respectively, compared with non-treated plants. In contrast, tansy extracts reduced chlorophyll content (by up to 78%) and induced moderate stress. The research highlights the potential of natural fungicides to protect plants effectively while minimizing environmental and human health risks compared to conventional chemicals.

The yeast strain Yarrowia lipolytica IPS 21 was tested for its ability to produce the protease enzyme on analytically pure carbon sources as well as on waste carbon sources. It was confirmed that the yeast Y. lipolytica IPS21 can have a higher proteolytic activity in the presence of waste carbon sources in chrome-tanned leather shavings (CTLS) than on yeast extract alone. This is confirmed by the high concentration of amino acids in samples with CTLS, suggesting increased degradation of CTLS by Y. lipolytica or secretion of proteases into the medium. It was also confirmed that metals accumulate mainly in the biomass and not in the supernatant. The biomass was also found to contain high levels of Ca, K and P, which are essential for plant growth. These results show that Y. lipolytica strain IPS21 can be used for the production of extracellular alkaline proteases and for the degradation of protein waste.

The objective of this study was to investigate the effects of the combined use of plant growth stimulants, including protein hydrolysates derived from animal waste and an azoxystrobin fungicide, during the cultivation of winter wheat ( Triticum aestivum L.). Three formulations were tested: collagen hydrolysate with sodium salicylate (1), collagen hydrolysate with titanium ascorbate (4a), and collagen and keratin hydrolysates with sodium salicylate (8). The collagen and keratin hydrolyzed extracts were obtained from tannery waste, specifically chromium leather waste, an important component of the leather industry’s circular economy. The experiments carried out in grow boxes demonstrated that the application of the new products in combination with fungicides resulted in an increased seedling length (9.6%, 10%, and 15.9% for preparations No. 1, 4a, and 8, respectively) and seedling fresh weight (8.5%, 7.9%, and 9% for preparations No. 1, 4a, and 8, respectively) compared to the control group without biostimulants. The use of preparation No. 8 also led to an increase in the nutrient and amino acids content of the plants. The prospective utilisation of protein biostimulants in crop production, encompassing those comprising salicylic acid and titanium ascorbate, has the potential to confer social, ecological and environmental benefits.