Selenium Enrichment of the Edible Medicinal Mushroom Antrodia camphorata by Submerged Fermentation
Abstract
Selenium (Se) is an essential nutrient element in human physiological metabolism and immune function. Supplementation of bioavailable Se will confer benefit on human life, especially when intake of this nutrient is inadequate. The edible and medicinal mushroom Antrodia camphorata is a unique fungus endemic to Taiwan, which has shown high therapeutic and nutritive value. This study is the first to demonstrate that A. camphorata can assimilate and transform sodium selenite into organic selenium. With an initial concentration of Se (IV) at 10 mg/L in 100 mL of the medium at 25 °C, the total selenium content in Se-enriched A. camphorata mycelia was 1281.3 ± 79.2 µg/g, in which the organic selenium content accounted for 88.1%. Further analysis demonstrated that selenium-enriched polysaccharide was the main form of Se present in A. camphorata (61.5% of the organic selenium). Four water-soluble Se-polysaccharide fractions were separated from A. camphorata, and ACP II was the major fraction of Se-polysaccharide. The scavenging efficiency of Se-polysaccharides on DPPH and ABTS radicals was determined, proving that selenium enrichment dramatically improved the in vitro antioxidant capacity of A. camphorata polysaccharide. Therefore, the selenium accumulation and transformation ability of A. camphorata provides an opportunity for developing this beneficent fungus into a novel selenium-enriched dietary or medicinal supplement.
Figures 
Figure 1
Mycelial morphology of A. camphorata…
Figure 1
Mycelial morphology of A. camphorata mycelia (×40). Co, conidia; Mb, mycelium branch; Mt,…
Figure 1 Mycelial morphology of A. camphorata mycelia (×40). Co, conidia; Mb, mycelium branch; Mt, mycelium tip.
Figure 2
ITS gene sequence-generated phylogenetic tree.
Figure 2
ITS gene sequence-generated phylogenetic tree.
Figure 2 ITS gene sequence-generated phylogenetic tree.
Figure 3
A. camphorata mycelia were cultured…Figure 3
A. camphorata mycelia were cultured in solid media at different temperatures: ( A… Figure 3 A. camphorata mycelia were cultured in solid media at different temperatures: (A) cultured at 30 °C and (B) cultured at 25 °C.
Figure 4
Biomass and selenium-enriching capacity of…
Figure 4
Biomass and selenium-enriching capacity of A. camphorata at different concentrations of initial Se…
Figure 4 Biomass and selenium-enriching capacity of A. camphorata at different concentrations of initial Se (IV). Values with letters a, b, c, d, e, and f are significantly different across columns (p < 0.05).
Figure 5
Effects of the liquid filling…
Figure 5
Effects of the liquid filling volume and rotational speed on the selenium-enriching capacity…
Figure 5 Effects of the liquid filling volume and rotational speed on the selenium-enriching capacity and the biomass in shake flask with or without baffle: (A) effect of liquid filling volume in shake flask without baffle; (B) effect of liquid filling volume in shake flask with baffle; and (C) effect of rotational speed in shake flask without baffle. Values with letters a, b and c are significantly different across columns (p < 0.05).
Figure 6
Fractionation of A. camphorata polysaccharides…
Figure 6
Fractionation of A. camphorata polysaccharides by ion-exchange chromatography and size-exclusion chromatography. Crude polysaccharides…
Figure 6 Fractionation of A. camphorata polysaccharides by ion-exchange chromatography and size-exclusion chromatography. Crude polysaccharides on HiTrap Q FF (A), and fraction II on Seuperdex 200 Increase 10/300 GL column (B).
Figure 7
Antioxidant activity tests of ACP:…
Figure 7
Antioxidant activity tests of ACP: ( A ) ABTS radical scavenging activity, and…
Figure 7 Antioxidant activity tests of ACP: (A) ABTS radical scavenging activity, and (B) DPPH radical scavenging activity.
Figure 8
Selenium Standard Curve determined by…
Figure 8
Selenium Standard Curve determined by HG-AFS.
Figure 8 Selenium Standard Curve determined by HG-AFS. All figures (8)