Mining and characterization of 3-ketosteroid-∆1-dehydrogenases from Arthrobacter simplex genome and applications for steroid dehydrogenation

Steroid ∆1-dehydrogenation catalyzed by 3-ketosteroid-∆1-dehydrogenase (KsdD) plays key roles in steroid biodegradation and industrial steroid modification. In this study, five KsdDs from Arthrobacter simplex were heterogeneously expressed, purified and characterized. Of the five KsdDs, KsdD1 and KsdD2 showed the highest catalytic activity toward androstenedione (AD), cortisone and cortisone acetate (CA) except for KsdD4. Molecular dynamics (MD) simulations indicated that KsdD1 and KsdD2 have relatively higher binding energy in substrate recognition. Furthermore, Compared with KsdD1, KsdD2 showed higher stability according to root mean square fluctuations (RMSF) and root mean square deviations (RMSD) analysis. To further increase the ∆1-dehydrogenation efficiency, a novel deep eutectic solvent (DES) was used in the reaction system. The highest conversion was obtained using KsdD2 as the biocatalyst in a choline chloride:glycerol (ChCl:Gly) containing system. To our best knowledge, this is the first report on the purification and characterization of KsdD1 and KsdD2 from Arthrobacter simplex. KsdD2 has been shown to be a promising candidate for developing efficient process for industrial production of steroid-based pharmaceuticals.