Industrial Biotransformations

-Lactamase
Aureobacterium sp.
1) Reaction conditions
[1]: 1.83 M, 200 g · L –1 [109.05 g · mol –1 ]
T: 70 °C
medium: aqueous
reaction type: carboxylic acid amide hydrolysis
catalyst: immobilized enzyme
enzyme: β-lactamhydrolase (β-lactamase)
strain: Aureobacterium sp.
CAS (enzyme): [9001–74–5]
2) Remarks
1 (+)-1
EC 3.5.2.6
1 = 2-azabicylo[2.2.1]hept-5-en-3-one (γ-lactam)
2 = 4-amino-cyclopent-2-enecarboxylic acid Celltech Group plc
Fig. 3.5.2.6 – 1
O
NH
E
● The enzyme is purified (ammonium sulphate fractionation and anion-exchange chromatography)
and immobilized on a glutaraldehyde-activated solid support.
● The biotransformation is operated in a batch reaction wherein an aqueous solution of the racemic
lactam is circulated through the fixed bed of immobilized enzyme.
● The reaction is complete when the (–)-enantiomer is hydrolyzed completely (E-value > 7,000).
● The stability of the enzyme is improved by immobilization so that a nearly steady-state production
can be achieved for more than 6 months.
● To separate the amino acid from the reaction mixture the solution has to be slurried with acetone.
The (+)-lactam stays in solution while the amino acid crystallizes and can be removed by
filtration.
● In comparison to the chemical resolution in which the lactam is converted to the salt of the
amino acid, the biotransformation produces the neutral, zwitter-ionic form of the acid.
420
N
O
+
- OOC
(-)-2
NH 3 +