Screening of Candida sp. for N-dealkylation of codeine

A number of Candida species were selected in order to test their ability to N- or O-demethylate codeine. Complex media and chemically defined media used in our experiments. Transformation products were analysed by reversed phase HPLC and TLC methods. N- and O-demethylation of codeine was performed by C. tropicalis NCYC 997, NCYC 405, NCYC 470 and C. albicans LSHTM 3153. Transformation by C. tropicalis NCYC 997 had better results. N- and O-demethylation occurred in the chemically defined medium. Change in the colour of the transformation mixture, in cultures containing more than 5 mmol.l-1 codeine, was attributed to codeine N-oxide, but its presence was not confirmed by HPLC. N- and O-demethylation of codeine by Candida sp. was compared to that occurred in mammals.