Minor Ginsenoside Production By The Enzyme From Novel Bacteria

Ginsenoside Rg3 with anti-tumor activity was given high evaluation of pHarmacology activity and developing prospect.But the percentage of ginsenoside Rg3 contents in ginseng is as low as 0.03‰,as well as the press of Rg3 abstraction is complicated and costly,so it was out of practice to get Rg3 directly from ginseng.The high contents protopanaxadiol type saponins such as Ra1?Ra2?Ra3?Rb1?Rb2?Rb3?Rc?Rd?F2 have the similar sapogenin and different glycoside structure and it is worthy to use enzyme to get Rg3 through protopanaxadiol type saponins hydrolysis reaction.In order to get the proper enzyme to transform protopanaxadiol type saponins into Rg3,20 kinds of bacterium from Kaist(Korea)were selected in this experiment.Arthrobacter sp.3 and Rhodopseudomonas sp.18 were definite as the aim bacterium.The results showed that optimal culture conditions for the sp.3 were temperature(25?),time(48h),in No.2 culture medium with 0.02%Rutin as inducer,as well as the optimal culture conditions for the sp.18 were temperature(30?),time(80h),in No.2 culture medium with 0.02%Rutin as inducer.For sp.3,it entered logarithm growth period after 6 h culture and present peak growth after 32 h then keep relative stable peace of growth during 32h to 40h and after 40h culture the bacterium begin to die,the highest enzyme activity was appeared after 36h and the content of Rg3 after biotransformation has increased to be 40%.As for sp.GS3082,it entered logarithm growth period after 44 h culture and present peak growth after 72 h then keep relative stable peace of growth during 72h to 84h and after 84h culture the bacterium begin to die,the highest enzyme activity was appeared after 82h and the content of Rg3 after biotransformation has increased to be 33%.The enzyme from the aim bacteria hydrolyzed protopanaxadiol type saponins into Rg3,Rh2 and sapogenin etal.The enzyme from sp.3 had higher activity to produce Rg3 with the yield of 40%while the yield of sp.18 is only 33%.We use DEAE-cellulose column and the SDS-PAGE to purify the aim enzyme as well as molecule weight estimating.For the enzyme from sp.3 was purified as one zone in tube 33 and 34 and the molecule weight of it was about 64 KDa.The enzyme from sp.18 present tow zones in SDS-PAGE which need advanced purification.