Stereoselective multi-step reduction of dehydrocholic acid with hydroxysteroid dehydrogenases

Boqiao Sun, doctoral thesis Technische Universität München, 2014

The two-step reduction of dehydrocholic acid to 12-keto-ursodeoxycholic acid is the biocatalytic step in the chemo-enzymatic synthesis of ursodeoxycholic acid. Escherichia coli whole-cell biocatalysts expressing hydroxysteroid dehydrogenases were designed to enable a simple biocatalytic one-pot process. The process was analyzed and optimized through modeling. When applying even low amounts of the whole cell biocatalyst on a liter-scale,  28 g/L dehydrocholic acid could be completely converted to the desired pure chiral product and high space-time yields of 120 g/L/d were achieved.

Publications

• Sun B, Hartl F, Castiglione K, Weuster-Botz D (2015): Dynamic mechanistic modeling of the multienzymatic one-pot reduction of dehydrocholic acid to 12-keto ursodeoxycholic acid with competing substrates and cofactors. Biotechnol Prog 31: 375–386.
• Sun B, Kantzow C, Bresch S, Castiglione K, Weuster-Botz D (2013): Multi-enzymatic one-pot reduction of dehydrocholic acid to 12-keto-ursodeoxycholic acid with whole-cell biocatalysts. Biotechnol Bioeng 110: 68-77.
• Braun M, Sun B, Anselment B, Weuster-Botz D (2012): Novel whole-cell biocatalysis with recombinant hydroxysteroid dehydrogenases for the asymmetric reduction of dehydrocholic acid. Appl Microbiol Biotechnol 95: 1457-1468.