Effect of various sodium salt ions on the cordycepin and adenosine production of C. militaris-fermented oats in solid culture. DOW (a), Na-SW (b), NaNO3 (c), Na2SO4 (d), Na3PO4 (e), or NaCl (f) solution was added to the solid substrate of C. militaris during solid culture, respectively. NaNO3, Na2SO4, Na3PO4 and NaCl solution included equal SO4
−, and Cl− concentration to that in 30X or 60X DOW, respectively. Na-SW was a mixture of the four sodium salt solutions. Data are presented as mean ± SD (n = 3). *, **, *** indicated the significant difference (p < 0.05, p < 0.01, p < 0.001, respectively) as compared with UPW.