To evaluate the
possibility of crystallization as a method of purification, cordycepin
was tentatively crystallized from the culture filtrate as follows: (i)
the freeze-dried filtrate of the culture broth (total cordycepin
content approximately 15 g) was re-dissolved in distilled water at
70C to produce a 20 g/L cordycepin solution; (ii) the solution was
filtered through a membrane filter (pore size; 5-mm, Mixed cellulose ester A500A090C, Advantec, Japan) under reduced pressure for
removal of insoluble components; (iii) the supernatant was left in he refrigerator (5C) over night; (iv) the crystallized cordycepin
was recovered with a filter paper (pore size, 7-mm); (v) the unwanted components like colored substances were removed by rinse
with chilled distilled water; (vi) the crystallized cordycepin was
freeze-dried