Nutritional Requirements for Growth of Agaricus brasiliensis

ABSTRACT. The nutritional requirements of A. brasiliensis in culture media were assessed by supplementing a basal medium (g L-1): (glucose, 10, KH2PO4, 1, MgSO4.7H2O, 0.5, [NH4]2SO4, 1, pH 5.5) with CaCl2, trace elements (FeSO4.7H2O; MnCl2.4H2O; ZnSO4.7H2O; CuSO4.5H2O), casein, yeast extract, peptone, B-vitamins or amino acids. Evaluations were based on the mycelial growth in solid or liquid culture (mm day-1 or mg day-1) and visual analysis of the colony. The addition of CaCl2 and trace elements was very important for the major mycelial growth of the fungi. The addition of casein and inositol to the medium did not have a significant effect on growth. The best growth result in solid medium was obtained with the basal medium plus the addition of yeast extract and peptone. In relation to the other nutrient sources, the mycelial growth in the presence of amino acids darkened the medium after two weeks. The addition of B-vitamins to the basal medium lead to slower mycelial growth; however, growth was more visually dense when compared to other nutritional sources. B-vitamins added separately did not have the same result, suggesting that the fungus requires two or more vitamins at the same time for better mycelial growth. Key words: mushroom, trace elements, B-vitamins, amino acids