Effect of Copper and Zinc addition to peat casing on A. blazei Murril production

GONZÁLEZ MATUTE, RAMIRO; FIGLAS, DÉBORA; CURVETTO, NÉSTOR

Peat: Formation and Biological Effects

Nova Science Pub Inc

Lugar: Nueva York; Año: 2011; p. 1 - 17

The use of peat, as a casing material, in the Agaricus spp. mushroom industry is a common practice. Sphagnum peat moss is the most employed, often mixed with other peat types or materials such as charcoal, and with the addition of calcium carbonate (pH adjustment) and water (ca. 75 %), and applied on top of the mushroom colonized substrate to retain water on the growing beds and to promote mushroom fruit body formation. Agaricus blazei Murrill is an edible mushroom highly appreciated in the medicinal worldwide market, mainly for its immune stimulating effects. It is also known as an efficient metal accumulator; particularly, copper and zinc can be absorbed by its mycelium and assimilated into metal organic compounds, which are accumulated in the mushroom carpophores, then resulting in a metal bioavailable source with a potential use as dietary supplements. Copper and zinc are essential to human health, based on their role in metalloenzymes and as cofactors of a large number of enzymes. Lack or deficiency of these metals may cause certain illnesses or physiological disorders, while the excess can be highly toxic. The aims of this chapter were to evaluate the possibility to obtain Agaricus blazei fruit bodies enriched with copper or zinc, following the addition of the salt solutions of these oligoelements into the peat moss during the casing preparation or when watering the casing bed, thus challenging their growing mycelia with different doses (100 ppm or 200 ppm Cu2+ or Zn2+), and to evaluate the mycelium growth, mushroom productivity and metal bioavailability from these enriched mushrooms. Results showed that either, the addition of a ZnSO4 solution in the casing (100 ppm or 200 ppm Zn2+) or when watering (100 ppm Zn2+) the casing bed, significantly increased the A. blazei crop yield. Also, the addition of different concentrations of Cu2+ or Zn2+ during preparation or watering of the peat casing resulted in the fruit body accumulation of these oligoelements, with the highest Cu2+ accumulation when its salt solution was added during the casing preparation, while the same was true for Zn2+ when its salt solution was added during the watering of the casing bed. The metal bioavailability from metal enriched A. blazei fruit bodies increased in a metal dose-dependent way. The higher bioavailability, for both metals, was observed when they were incorporated during the peat casing preparation in comparison with their application in the watering of the casing bed.