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Ganoderma lucidum is a widely recognized medicinal mushroom. The bioaccumulation and potential bioavailability of copper (Cu) and zinc (Zn), which are essentials for human health, were analyzed in G. lucidum mycelium and fruit bodies grown in the presence of these metals to test their potential utility as a food dietary supplement. Mycelia grown in culture medium with non-mycotoxic doses of Cu or Zn (25 and 50 mg/kg) were selected for evaluation of the bioavailability of these metals in the gastrointestinal tract by using an in vitro simulated digestion system. One gram of dried mycelium grown in the presence of 50 mg/kg Cu or Zn showed a bioavailability of 19% for Cu and 2% for Zn of the recommended daily intake (RDI). When production of fruit bodies was evaluated, the highest biological efficiency (23%) was reached when the substrate was enriched with 100 mg/kg Cu. Cu and Zn contents obtained either before or after digestion of fruit bodies from all metal-enriched treatments were substantially lower than those from metal-enriched mycelia. The metal bioavailability was also low: 1.5% of the Cu RDI and almost negligible for Zn. The results are discussed in relation to the RDI values exhibited by two commercial supplements. The potential incorporation of these mineral-enriched mycelia/fruit bodies in capsules, infusions, and dietary supplements is evaluated.

Agaricus blazei Murrill is usually cultivated using the same biphasic composting method employed for A. bisporus. Because cultivation of A. blazei on traditional A. bisporus composts poses some disadvantages, non-composted substrates were studied for A. blazei cultivation. Mycelial growth rate and productive performance of A. blazei were evaluated on substrates containing sunflower seed hulls, Pleurotus spp. spent mushroom substrate, or their combination, in the absence or in the presence of different supplements (vermicompost, peat or brewery residues). Substrates were prepared by initially soaking them and then they were sterilized (1 atm for 120 min). In addition, each substrate's degradation was measured after cultivation by obtaining the lignin, cellulose, hemicellulose, organic matter, total fiber, ash, carbon and nitrogen contents before spawn-run and at the end of two flushes of A. blazei. The cultivation of A. blazei on non-composted substrates is possible and with a low rate of contamination when using the spent mushroom substrate as the main component or combined 50:50 with sunflower seed hulls. In addition, the best yields were obtained on those substrates containing spent Pleurotus mushroom substrate with supplements and those mixtures with sunflower seed hulls and vermicompost. These yields were similar to those reported on composted substrates. Substrate changes in composition measured at the end of two flushes indicate that the lignin-hemicellulose fraction was preferentially used and that the substrates exhibiting the best yield showed greater biodegradation of lignin-hemicellulose fraction than the others did.

Agaricus blazei is an edible mushroom with medicinal properties. To obtain organic combinations of potential utility as a food dietary supplement, the accumulation and potential bioavailability of copper (Cu) and zinc (Zn) on mycelium grown in the presence of these metals were studied. At 400 ppm, the mycelium accumulated 449 and 163 times the basal content of Cu and Zn, respectively. When mycelia cultivated with nonmycotoxic concentrations of Cu or Zn (100 and 200 ppm) were subjected to sequential chemical extraction and simulated gastrointestinal digestion, close to 90% of the metals accumulated in the available nonresidual fraction, which was similar to or better than the values found in two commercial supplements. The solubility in the simulated digestive fluids was 30-34% and 18-33%, i.e., 60-98% and 9-11% of the recommended daily intake for Cu and Zn, respectively, with only 1 g of mycelium.