Immobilised-enzyme processes

Immobilise -enzyme systems are used where they offer cost advantages to users on the basis of total manufacturing costs. The plant size needed for continuous processes is two orders of magnitude smaller than that required for batch processes using free enzymes. The capital costs are, therefore, considerably smaller and the plant may be prefabricated cheaply off-site Immobilised enzymes offer greatly increased productivity on an enzyme weight basis and also often provide process advantages (see Chapter 3) Currently used immobilised-enzyme processes are given in Table 5.1.

Enzyme	EC number	Product
Aminoacylase	3.5.1.14	L-Amino acids
Aspartate ammonia-lyase	4.3.1.1	L-Aspartic acid
Aspartate 4-decarboxylase	4.1.1.12	L-Alanine
Cyanidase	3.5.5.x	Formic acid (from waste cyanide)
Glucoamylase	3.2.1.3	D-Glucose
Glucose isomerase	5.3.1.5	High -fructose corn syrup
Histidine ammonia-lyase	4.3.1.3	Urocanic acid
Hydantoinase^a	3.5.2.2	D- and L-amino acids
Invertase	3.2.1.26	Invert sugar
Lactase	3.2.1.23	Lactose-free milk and whey
Lipase	3.1.1.3	Cocoa butter substitutes
Nitrile hydratase	4.2.I.x	Acrylamide
Penicillin amidases	3.5.1.11	Penicillins
Raffinase	3.2.1.22	Raffinose-free solutions
Thermolysin	3.2.24.4	Aspartame