[Objective] This study aimed to select stains for transforming podophyllotoxin, to isolate the transformation product and to identify the structure. [ Method~ Structure of podophyllotoxin was modified with microbial batch transformation method. Podophyllotoxin and its transformation products were detected by using TLC and HPLC methods to select strains with ability to transform podophyllotoxin. Scale-up fermentation of one podophyllotoxin-transforming strain was carried out and the fermented material was extracted with EtoAc, isolated with conventional silica gel column chromatography, structure of the transformation product was identified by using classic spectroscopy technology. [ Result ] Based on researches of pedophyllotoxin transformation, seven strains with ability to transform po- dophyllotoxin were selected, including BS. Str-1, BS. Str-2, BS. Str-3, BS. Str-7, BS. Str-18, BS. Str-21 and BS. Str-29. By scale up fermentation, the only trans- formation product of BS. Str-21 strain was extracted and isolated, which was identified as picropodophyllotoxin. [ Conclusion] This study demonstrates that podo- phyllotoxin derivatives can be obtained by biotransformation methods, which lays the foundation for acquisition of natural drugs with high anti-tumor activity.
