Beilstein J. Org. Chem.2018,14, 470–483, doi:10.3762/bjoc.14.33
times and lower costs for the chemical and enzymatic reactions involved.
Keywords: bile acids; biotransformation; hydroxysteroiddehydrogenases; production process; UDCA; Introduction
Ursodeoxycholic acid (UDCA), is applied in the pharmaceutical industry (Figure 1) [1]. As reported in several papers
. Ideally, there is the possibility of using other types of less volatile compounds but no reports thereof have been found.
12α-Hydroxysteroid dehydrogenase
12α-Hydroxysteroiddehydrogenases (12α-HSDH) are particularly interesting for the selective oxidation of the 12-hydroxy group of CA (Figure 4). These
presented in the next paragraphs.
7α-Hydroxysteroiddehydrogenases (7α-HSDH)
These enzymes are able to oxidise specifically the α-hydroxy group at C7 together with the concomitant reduction of NAD+ or NADP+ (Figure 5). All of them are part of the group of the short chain dehydrogenases/reductases (SDR