Molecular cloning, expression of CPR gene from Rhizopus oryzae into Rhizopus nigericans and its application in the 11α-hydroxylation of 16α, 17-epoxy-progesterone

• The pCB1004-PgpdA was first used for cloning and expressing the CPR gene.
• CPR gene was first strengthened in R. nigericans.
• The strengthened expression of CPR gene can make great economic sense in steroid production.

The hydroxylations of the steroid skeleton structure are catalyzed by a family of enzymes, the cytochromes P450 (CYPs). In this study, the pCB1004-PgpdA plasmid was used for cloning the cytochrome P450 reductase (CPR) gene from Rhizopus oryzae into Rhizopus nigericans to strengthen the expression of CPR gene in R. nigericans with REMI (Restriction Enzyme Mediate Integration) mediated protoplast transformation. The conditions for the protoplast production of R. nigericans were optimized as follows: 75 μg/mL yatalase, 50 μg/mL lywallzyme, fungus age of 12 h, digestion time of 3 h and digestion temperature of 30 °C. REMI mediated protoplast transformation with plasmid pCB1004-PgpdA into R. nigericans was performed to construct the transformants. More than 30 transformants were successfully selected from the hygromycin B-resistant plates and 6 transformants had the abilities to improve the biotransformation of 16α, 17-epoxyprogesterone. The highest biotransformation rate of the transformants was 65.38%, which was 7.06% higher than that of the original strain.