A comparative analysis of mineral elements in the mycelia and the fruiting bodies of shiitake mushrooms

Abstract

Mineral elements in four strains of Lentinula edodes mycelia grown on a defined media and fruiting bodies of shiitake mushroom grown on sawdust along with three commercially available shiitake mushrooms were analyzed to determine major and minor element levels of Na, K, Ca, Mg, Al, Fe, Mn, Cu, Pb and Ni on a dry weight basis. Analyses indicated Na (1646-5322 mg kg-1), K (5379-10320 mg kg-1) and P (3201-8184 mg kg-1) as most abundant minerals in mycelia followed by other major elements. Trace/heavy metals in mycelia show Zn (19.0-49.7 mg kg-1), Fe (31.8-41.6 mg kg-1), Cu (9.2-12.7 mg kg-1), Mn (2.2-48.5 mg kg-1), Pb (0.02-2.5 mg kg-1) and Ni (0.39-1.1 mg kg-1) with significantly higher accumulation of Zn in the mycelia of heat-resistant strain, LE 054 and significantly low levels of Mn in both heat-resistant strains relative to other strains (p<0.05). Major element ranged in fruiting bodies of mushroom collection suggest that K (13.2-62.2 g kg-1), P (7.8-54.5 g kg-1) and Mg (3.4-6.5 g kg-1) as most abundant elements followed by Ca (179.8-1698 mg kg-1), Na (191.3-3448 mg kg-1) and Al (15.3-79.5 mg kg-1). The Al levels resemble the amounts reported for Al accumulating mushroom species. Most abundant trace/heavy metals in the mushroom collection were Zn (59.3-283.9 mg kg-1) followed by Fe (44.4-125.1 mg kg-1), Mn (18.2-73.2 mg kg-1) and Cu (13.7-182.4 mg kg-1). Only trace amounts of toxic heavy metals, Cd (0.27-3.7 mg kg-1), Co (0-0.87 mg kg-1), Ni (0-0.54 mg kg-1) and Pb (0-2.2 mg kg-1) were found in mushroom collection. In some instances, preferential accumulation of certain elements was detected in caps relative to stems.