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Major Products Obtained Using Immobilized Enzymes (3)

Enzyme

Product

Glucose isomerase

High-fructose corn syrup

Amino acid acylase

Amino acid production

Penicillin acylase

Semi-synthetic penicillins

Nitrile hydratase

Acrylamide

ß-Galactosidase

Hydrolyzed lactose (whey)

2. History of Enzyme Immobilization

It is possible to visualize three steps in the development of immobilized biotatalysts (Table 3). In the first step, at the beginning of the 19th century, immobilized microorganisms were being employed industrially on an empirical basis. This was the case with both the microbial production of vinegar (by letting alcohol-containing solution trickle over wood shavings overgrown with bacteria) and the development of the trickling filter—or percolating process—for waste water clarification (11).

The modern history of enzyme immobilization goes back to the late 1940s but much of the early work was largely ignored by biochemists because it was primarily published in journals of other disciplines (12). The basis of the present technologies was developed in the 1960s and there was an explosive increase in publications. (4). In the second step, only immobilized single enzymes were used but by the 1970s more complex systems, including two-enzyme reactions with co-factor regeneration and living cells, were developed (13). As an example of the latter we can mention the production L-aminoacids from a-keto acids by stereoselective reductive amination with L-aminoacid dehydrogenase. The process involves the consume of nicotinamide adenine dinucleotide (NADH) and regeneration of the coenzyme by coupling the amination with the enzymatic oxidation of formic acid to carbon dioxide with concomitant reduction of NAD+ to NADH, in the reaction catalyzed by the second enzyme, formate dehydrogenase.

Table 3

Steps in the Development of Immobilized Enzymes (11)

Table 3

Steps in the Development of Immobilized Enzymes (11)

Step

Date

Use

First

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