A Possibility to Use Selected Crop Post-Extraction Wastes to Improve the Composition of Cultivated Mushroom Pleurotus citrinopileatus

Impact of Spent Mushroom Substrate Combined with Hydroponic Leafy Vegetable Roots on Pleurotus citrinopileatus Productivity and Fruit Bodies Biological Properties

Agricultural activities produce large quantities of organic byproducts and waste rich in lignocellulosic materials, which are not sufficiently utilized. In this study, alternative agricultural waste products, namely, spent mushroom substrate (SMS) from the cultivation of edible Pleurotus ostreatus mushrooms and the roots of leafy vegetables from hydroponic cultivation (HRL), were evaluated for their potential to be used as substrates for the cultivation of Pleurotus citrinopileatus and their effects on the quality, the nutritional value, the chemical properties (lipid, protein, carbohydrate, ash, fatty acid and carbohydrate composition) and the bioactive content (total phenolic compounds and antioxidant activity) of produced mushrooms. SMS and HRL (in different ratios with and without additives) and wheat straw with additives (WS-control) were used. During incubation, the linear growth rate of the mycelium (Kr, mm/day) was measured and used for screening. Mushroom cultivation took place in bags, where several characteristics were examined: earliness (duration between the day of substrate inoculation and the day of first harvest) and biological efficiency (B.E. %, the ratio of the weight of fresh mushrooms produced per dry weight of the substrate × 100). Furthermore, this study aimed to investigate the effect of the protein extract (PE) and carbohydrate extract (CE) of P. citrinopileatus after in vitro digestion (fraction less than 3kDa: PE-DP-3; digestate fraction: CE-D, respectively) on the expression of antioxidant-related genes in the THP-1 cell line. The results showed that mushrooms grown on SMS 50%-HRL 40% had the fastest growth (6.1 mm/d) and the highest protein and lipid contents (34.7% d.w.; 5.1% d.w.). The highest B.E. (73.5%), total carbohydrate (65.7%) and total phenolic compound (60.2 mg GAE/g d.w.) values were recorded on the control substrate. Antioxidant activity was observed in all extracts; the total flavonoid content was low in the samples, and the maximum total triterpene value was detected in SMS 80%-HRL 20% (9.8 mg UA/g d.w.). In all mushrooms, linoleic acid (C18:2) was the main fatty acid (above 60%), and fructose was the dominant individual saccharide. In the investigation of the regulation pathway, NFE2L2 gene expression was upregulated only in the SMS 60%-HRL 40% intervention during incubation with CE-D samples. Additionally, the transcription levels of antioxidant-related genes, SOD1, CAT, HMOX1 and GSR, were increased in the SMS 60-30% intervention. Compared to WS, the alternative substrates are observed to trigger a pathway concerning CE that may resist oxidative stress. This study supports the utilization of agricultural byproducts through sustainable and environmentally friendly practices while simultaneously producing high-value-added products such as mushrooms. Therefore, alternative substrates, particularly those containing HRL, could serve as natural sources of antioxidant potential.

Bioprospecting the Biological Effects of Cultivating Pleurotus ostreatus Mushrooms from Selected Agro-Wastes and Maize Flour Supplements

Pleurotus mushrooms are valuable food supplements with health and environmental restorative potential. In this paper, we sought to evaluate the biological activities and profile the bioactive compounds found in Pleurotus ostreatus cultivated from agro-waste supplemented with maize flour. We investigated carbon to nitrogen (C/N), antimicrobial, antioxidant, and antimalarial potential for the varying supplementation during mushroom cultivation. GCMS was utilized for screening bioactive compounds found in P. ostreatus. Changes in supplementation directly correlate with changes in compound profiling. Nonetheless, some compounds were found to be common amongst the tested mushrooms, including pentadecanoic acid; 9,12-octadecadienoic acid, methyl ester; pentadecanoic acid, methyl ester; octadecanoic acid; and diisooctyl phthalate. The highest antimicrobial potential against Gram-positive Staphylococcus aureus was observed when maize flour supplements were increased to 12% and 18%. Our data demonstrated that the observed antioxidant (DPPH, ABTS, and reducing power) and antimicrobial activity could emanate from various supplementation conditions. Furthermore, supplementation has an impact on the mushroom yield and phytochemical profiles of the produced mushroom.

Influences of Some Aromatic Plants on Volatile Compounds and Bioactivity of Cultivated Pleurotus citrinopileatus and Pleurotus djamor

Two edible Pleurotus species, namely, Pleurotus citrinopileatus and Pleurotus djamor grown in the media of mulberry shavings which were substituted with myrtle, bay laurel, and rosemary leaves were studied. According to volatile profiles, 13 aldehydes, 8 ketones, 7 alcohols, 5 aromatic compounds and 4 terpenes were totally identified. Rosemary leaves were very effective for decreasing the concentrations of some oxidation products in Pleurotus citrinopileatus, but the same impact was not seen in Pleurotus djamor. The high amount of benzaldehyde (41.80 %) detected in bay laurel medium might have played a role in preventing bioactivity. Control Pleurotus citrinopileatus and Pleurotus djamor had a total phenolic content of 4284.89 and 3080.04 mg GAE per kg DM, respectively, and the enrichment of composts with aromatic plant leaves caused significant differences in Pleurotus djamor (p<0.05). Myrtle addition increased total phenolic content and antioxidant activities (by DPPH and FRAP assays) of Pleurotus djamor mushroom as 342.29 mg GAE/kg DM, 0.43 μmol TE/g DM and 2.07 μmol TE/g DM, respectively, when compared to intact one.