Enhancing the lithium content of white button mushrooms Agaricus bisporus using LiNO3 fortified compost: effects on the uptake of Li and other trace elements

Attempts to bio-enrich fungal biomass with an essential trace elements to produce dietary supplements have some tradition and an example is selenium. Lithium salts have medical applications, but safer forms are sought after, and lithiated foods and food supplements may be an alternative. This study evaluated the lithiation of white Agaricus bisporus mushrooms using commercial compost fortified with LiNO ₃ and investigated the effects on co-accumulation of trace elements. The fortifications at levels of 1.0, 5.0, 10, 50 and 100 mg·kg ⁻¹ dw, resulted in corresponding median increases in mushroom Li concentrations of 0.74, 5.0, 7.4, 19 and 21 mg kg ⁻¹ dw, respectively, relative to 0.031 mg kg ⁻¹ dw in control mushrooms. The bio-concentration potential for Li uptake decreased at higher levels of fortification, with saturation occurring at 100 mg·kg ⁻¹, and the level of 500 mg kg ⁻¹ mycelium failed to produce mushrooms. The compost fortification resulted in up to several hundred-fold enrichment of mushrooms compared to those grown on control compost, underlining their potential therapeutic use. At higher fortification levels, some effects were seen on the co-accumulation of other elements, such as Ag (stems), As, Cd, Cr, Cs, Cu, Hg (stems), Mn, Rb, Sr, U (stems) and Zn; 0.05 < p < 0.10), but no effects were seen for Ag (caps), Al, Ba, Co, Hg (caps) Ni, Tl, U (caps), and V (p > 0.05).