cooperated biotransformation of ginsenoside extracts into ginsenoside 20srg3 by three thermostable glycosidases aims the aim of this work was to transform ginsenoside extract into the pharmacologically active minor ginsenoside 20srg3 by three thermostable glycosidasesmethods and results the gh1 thermostable betaglucosidase tpebgl1 from thermotoga petrophlia was found to have the ability to convert ginsenosides rb1 and rb2 its properties concerning ginsenoside conversion were systematically investigated it had high specific activity on pnpg 16220 u mg1 and pnparp 2214 u mg1 the km and vmax of tpebgl1 for pnpg were 028 mmol l1 and 4702 u mg1 and for pnparp were 1730 mmol l1 and 7428 u mg1 therefore it could successfully convert ginsenosides rb1 and rb2 into ginsenoside rd which has been proven by experiments in this paper then tpebgl1 also had good tolerance to glucose and some organic solvents these made tpebgl1 a good catalyst candidate for industrial application finally it was applied to convert ginsenoside extract into the pharmacologically active minor ginsenoside 20srg3 combined with thermostable ginsenoside rc converting 16larabinofranosidase ttafs and ginsenoside rd converting glucosidase tpebgl3 a quantity of 10 g l1 of ginsenoside extract was transformed into 393 g l1 of rg3 at 90c ph 50 for 3 h with a corresponding molar conversion of 9819conclusion the thermostable enzyme tpebgl1 was found to be a ginsenosideconverting enzyme and successfully applied in the preparation of ginsenoside 20srg3 from ginsenoside extract the threestep cooperate transformation system of ginsenoside extract was established by using tpebgl1 ttafs a thermostable ginsenoside rc converting 16larabinofranosidase and tpebgl3 a thermostable ginsenoside rb1 converting glucosidasesignificance and impact of the study converting all the major ginsenosides into protopanaxadioltype ginsenoside extract would greatly reduce the cost of ginsenoside rg3 preparation enzymes from thermophilic bacteria can meet the requirement of higher reaction temperatures in industrial reactions for substrate solubility promotion and bacterial contamination prevention