Impact of bioaccumulated selenium on nutraceutical properties and volatile compounds in submerged fermented Pleurotus eryngii mycelia

The present study highlighted the effect of micronutrient selenium in liquid cultured Pleurotus eryngii (PE) mycelia by supplementing sodium selenite (Na2SeO3) in the range of 2.5–20 μg/ml in dextrose-soya peptone medium. The produced mycelia was evaluated for biomass yield, selenium bioaccumulation, nutraceuticals, and bioactive compounds using the methods lyophilization, ICP-MS, HPLC, and GC–MS, respectively. Maximum biomass yield, 13.55 g/L (yield, 67.75%) was obtained at 5 μg/ml Na2SeO3. However, biomass growth got inhibited at higher Se concentration, that is, 7.46 g/L, yield 37.3% at 20 μg/ml Na2SeO3. Bioaccumulation of Se in the mycelia was increased to 338.43 μg/g from 1.26 μg/g (control). The protein fractions of mycelia accumulated most of the Se followed by polysaccharides and nucleic acids. The ergosterol, beta glucan, ergothioneine, phenolics, and antioxidant properties along with proteins and bioactives were improved significantly. Overall, the study revealed that incorporation of sodium selenite improved the nutraceutical properties of P. eryngii mycelia. Novelty impact statement The present study has demonstrated that nutraceutical properties (ergosterol, beta-glucans, phenolics, ergothioneine, volatile bioactives, and antioxidant properties) of submerged fermented edible Pleurotus eryngii (King Oyster) mycelia got increased by supplementation of essential micronutrient selenium in fermentation media in optimum concentrations. Mushroom mycelia as a bioaccumulators can be utilized effectively as a food supplement to treat mineral deficiency among human beings.