Iron and zinc mycelial bioaccumulation in Agaricus subrufescens strains

Abstract

Agaricus subrufescens, a basidiomycete native to Brazil, is worldwide cultivated due to its medicinal properties. This fungus is capable of bioaccumulating metals in the mycelial biomass when cultured in the presence of them; however, this capacity is little explored for functional food production. This study aimed to evaluate the amount of iron or zinc bioaccumulated in the vegetative mycelium of sixteen strains of A. subrufescens. Mycelia were grown in malt extract agar added with 50 mg/L of iron or with 7.5 mg/L of zinc. The metal bioaccumulation in the mycelial biomass was strain-dependent. In general, metal can inhibit or stimulate the mycelial growth ranging from -81 to +78% for iron and from -86 to +100% for zinc. The highest bioaccumulated iron and zinc concentrations in the mycelial biomass was 2,595.65 mg/kg and 1,655.83 mg/kg, respectively and occurred in the U4-4 strain. The supplementation of mycelial biomass using iron or zinc is an alternative to develop food supplements, that can be used both in the human and animal diet and in the prevention of diseases.