Ursodeoxycholic acid was efficiently synthesized by coenzyme self-circulation regeneration system
[Objective]To optimize the catalytic system for the efficient synthesis of ursodeoxycholic acid(UDCA)by using mutated highly active 7 α-hydroxysteroid dehydrogenase(7 α-HSDH)and 7 β-hydroxysteroid dehydrogenase(7 β-HSDH)coupled to form a set of coenzyme self-circulation regeneration catalytic systems.[Method]The 7α-HSDH mutant gene of Clostridium absonum DSM 599 and the 7 β-HSDH mutant gene of Ruminococcus torques ATCC 35915 were synthesized by arti-ficial optimization.The gradient optimization of 7α/β-HSDH induction temperature was carried out,and the conversion rate of chenodeoxycholic acid(CDCA)per unit time was used as the index to screen out the effects of glucose dehydrogenase(GDH),7α/β-HSDH addition ratio,temperature,pH and co-solvent on the catalytic reaction system.[Result]The optimal induction temperature of 7α/β-HSDH was 30 ℃,and the optimal process parameters for the synthesis of UDCA catalyzed by CDCA were as follows:the addition ratio of 7α/β-HSDH was 1:1.5,the temperature was 30 ℃,the pH value was 8.0,and the co-solvent was 0.4％Tween 80,and the conversion rate of CDCA in the catalytic reaction system could reach 90.8％.[Conclusion]The highly active 7α-HSDH and 7 β-HSDH can realize the self-recycling and regeneration of coenzymes,and the synthesis of UDCA can be catalyzed by CDCA cost-effectively through the optimization of the catalytic system.
NETL
NSTL
万方数据
