Composição mineral de uma linhagem de Pleurotus ostreatus cultivada em resíduos madeireiros e agroindustriais da região amazônica Mineral composition of Pleurotus ostreatus strain grown in wood and agroindustrial residues from the Amazon region

Mushrooms belonging to the Pleurotus gender are grown in several lignocellulosic substrates due to the decomposing activity of these organisms that result from their enzymatic metabolism. The objective of the present study was to analyze the mineral composition of Pleurotus ostreatus and the cultivation substrates prepared with wood and agroindustrial residues from the Amazon region. Macro (P, K, Ca and Mg) and micronutrients (Fe, Zn, Cu, Mn and Na) of mushroom and substrates were analyzed. Substrates were formulated from Simarouba amara Aubl. and Ochroma piramidale Cav. ex. Lam. sawdust and crushed Bactris gasipaes Kunth, and Saccharum officinarum (sugar cane). The samples were solubilized by acid digestion (nitric-peridrol). The elements Ca, Mg, Fe, Cu, Zn and Mn were determined by atomic absorption spectrometry; Na and K, by atomic emission, and P by colorimetry. The mineral composition of the mushroom varied with the substrate. Different substrates made possible the production of a mushroom rich in K, P, Mg, and Fe, essential to human nutrition and health. Potassium was the mineral with the highest content in the mushroom for all substrates tested (36.83-42.18 g.kg –1 ) followed by phosphorus (6.95-10.60 g.kg –1 ) and magnesium (1.57-2.50 g.kg –1 ).