Enhanced activity of 3α-hydroxysteroid dehydrogenase by addition of the co-solvent 1-butyl-3-methylimidazolium (l)-lactate in aqueous phase of biphasic systems for reductive production of steroids

The enzyme activity of 3α-hydrosteroid dehydrogenase (HSDH) was enhanced by the addition of the co-solvent 1-butyl-3-methylimidazolium (l)-lactate ([Bmim][lactate]) to 50 mM Tris–HCl buffer. When utilizing [Bmim][lactate], the reaction velocity of HSDH increased. Also, reductive production of androsterone was investigated in an aqueous–organic solvent biphasic system containing 5% [Bmim][lactate] as the co-solvent of aqueous phase. In a coupled-enzyme system comprising HSDH and formate dehydrogenase (FDH), a two-fold increase in production rate of androsterone was obtained when utilizing [Bmim][lactate] with NADH regeneration.