Industrial Biotransformations

Nitrile hydratase
Pseudomonas chlororaphis
1) Reaction conditions
[1]: 2.015 mol (organic phase), 218 kg [108.14 g · mol –1 ]
pH: 7.0
T: 5 °C
medium: two-phase: aqueous/organic
reaction type: hydration of CN
catalyst: immobilized whole cells
enzyme: nitrile hydro-lyase (nitrile hydratase, acrylonitrile hydratase, NHase,
L-NHase, H-NHase)
strain: Pseudomonas chlororaphis B23
CAS (enzyme): [82391–37–5]
2) Remarks
● The cells are immobilized in calcium alginate beads.
● For strain selection it is important that the cells do not show an amidase activity that would
further hydrolyze the amide to the carboxylic acid.
● By this method 13.6 t are produced in 58 repetitive batch cycles, starting from 12.7 t of adiponitrile.
● As by-product adipodiamide is formed.
1
E
EC 4.2.1.84
1 = adiponitrile
2 = 5-cyano-valeramide DuPont
Fig. 4.2.1.84 – 1
NC
CN
+ H2O
● This biotransformation is preferred to the chemical transformation due to a higher conversion and
selectivity, production of more product per weight of biomass (3,150 kg · kg –1 (dry cell weight), and
less waste:
NC
1
1 = adiponitrile
2 = 5-cyano-valeramide
3 = adipodiamide
Fig. 4.2.1.84 – 2
478
CN
H2O MnO2 130 °C
NC
2
NC
O
NH 2
2
+
O
H 2N
NH 2
O
3
O
NH 2