Industrial Biotransformations

Alcohol dehydrogenase
Rhodococcus erythropolis
1) Reaction conditions
[1]: 0.015 M, 1.95 g · L –1 [134,18 g · mol –1 ]
pH: 6.7
T: 25 °C
medium: aqueous
reaction type: redox reaction
catalyst: solubilized enzyme
enzyme: alcohol-NAD + oxidoreductase (alcohol dehydrogenase)
strain: Rhodococcus erythropolis
CAS (enzyme): [9031–72–5]
2) Remarks
1 NADH+H (S)-2
+
NAD +
EC 1.1.1.1
1 = 1-phenyl-2-propanone
2 = 1-phenyl-2-propanol Forschungszentrum Jülich GmbH
Fig. 1.1.1.1 – 1
E
O OH
● The cofactor regeneration is carried out with a formate dehydrogenase from Candida boidinii
(FDH = formate dehydrogenase, EC 1.2.1.2) utilizing formate that is oxidized to CO 2:
Fig. 1.1.1.1 – 2
NAD + NADH + H +
formate dehydrogenase
HCOOH
● This reactor concept is especially attractive for starting materials of low solubility. The starting
materials are directly titrated into the aqueous phase. The process consists of three loops: I:
aqueous loop with a hydrophilic ultra-filtration membrane retaining the enzymes; II: permeated
aqueous reaction solution products, starting materials and cofactors are passed through
the tube phase of the extraction module; III: organic solvent phase, containing extracted products
and starting materials.
● The charged cofactors (NAD + /NADH) remain in the aqueous loops I and II. Therefore only
deactivated cofactor needs to be replaced, resulting in an economically high total turnover
number (= ttn).
● The extraction module consists of microporous, hydrophobic hollow-fiber membranes. The
organic extraction solvent is recycled by continuous distillation. The product remains at the
bottom of the distillation column.
CO2
157