Enrichment of Culinary-Medicinal Oyster Mushroom, Pleurotus ostreatus (Agaricomycetes), Cultivated on the Straw Substrate with Zinc and Selenium.

Pleurotus ostreatus was cultivated on a commercially available wheat straw substrate enriched with Zn and Se. Various amounts of Zn (10, 50, and 100 mg) and Se (1, 5, and 10 mg) in suitable forms ((CH3COO)2Zn·2H2O, Zn(NO3)2·6H2O, and Na2SeO3·5H2O, respectively) were dissolved in 50 ml of deionized water and homogenously nebulized into the substrate block of 2.4 kg weight. The increase in the Zn content in fruiting bodies cultivated on the enriched substrate was relatively low compared with fruiting bodies cultivated on the substrate with no addition at the first flush. The application of different Zn compounds (acetate vs. nitrate) gave similar results. However, the addition of 1 mg of Se into the cultivation substrate block increased the content of Se in fruiting bodies to about 3-6 mg/kg dry matter. This content was one order of magnitude higher compared with the Se content in fruiting bodies harvested from the substrate with no Se addition (< 0.12-0.58 mg/kg dry matter). In the case of the addition of 5 mg of Se, there was a further significant increase in the content of this element to about 40-60 mg/kg dry matter.

Determination of Detrimental and Essential Elements in Medicinal Mushrooms Tylopilus felleus, Auricularia auricula-judae, and Pleurotus ostreatus (Agaricomycetes).

In this study, selected detrimental and essential elements were determined in fruiting bodies of Auricularia auricula-judae, Tylopilus felleus, and Pleurotus ostreatus medicinal mushrooms. A. auricula-judae and T. felleus were collected from sampling sites situated in South Bohemia, the Czech Republic, while P. ostreatus samples were obtained after cultivation under defined conditions on a straw substrate block. The elements were determined in underlying soils for T. felleus and bioconcentration factors were calculated. The analysis revealed that T. felleus accumulated Rb, Cd, Cu, Zn, Se, and Mg, with bioconcentration factors of 65.7, 2.47, 2.32, 1.93, 1.67, and 1.27, respectively. The analysis also revealed high contents (expressed as medians) of Ca (1600 mg/kg) and Mg (2040 mg/kg) in A. auricula-judae. On the other hand, the contents of detrimental elements such as Pb (0.10 mg/kg), Cd (0.33 mg/kg), and As (0.10 mg/kg) were lower. In cultivated P. ostreatus, lower element contents for Pb (< 0.05 mg/kg), Al (3.92 mg/kg), Ca (53.6 mg/kg), Mn (3.22 mg/kg), Ni (0.11 mg/kg), and Sr (0.93 mg/kg) were determined compared to both wild-growing A. auricula-judae and T. felleus. No negative effect on human health is expected for the mushroom species studied due to the accumulation of detrimental microelements.