The bioconversion of the lignan desoxypodophyllotoxin by cell suspensions of Linumflavum and of Podophyllum hexandrum was investigated. The apolar substrate could be easily dissolved in the culture medium at a concentration of 2 mM by complexation with dimethyl-/~-cyclodextrin. Growth parameters of the cell suspensions were not affected by either the addition of cyclodextrin itself, or when cyclodextrin-complexed desoxypodophyllotoxin was present in the medium. The complexed lignan disappeared from the medium within 7 days for both cell cultures. Cellularly only small amounts of desoxypodophyllotoxin were found. After feeding of desoxypodophyllotoxin, the cell culture of L. flavum accumulated 5-methoxypodophyllotoxin and 5-methoxypodophyllotoxin-/~-D-glucoside.After 7 days a total maximal content of 2.38% on a dry weight basis of 5-methoxypodophyllotoxin was formed, corresponding with 249 mg 1-l suspension. The highest bioconversion percentage of 52.3% was found at day 14.The desoxypodophyllotoxin-fed culture of P. hexandrum accumulated podophyllotoxin and its fl-D-glucoside with a maximal content of 2.87% on a dry weight basis after 9 days, corresponding with 192 mg 1-1 suspension. The highest bioconversion percentage of 33.2% was also found at day 9.