Enzyme Immobilization

An enzyme is a protein, or protein complex, that catalyses a chemical reaction. Like any catalyst, enzymes work by lowering the activation energy of a reaction, thus allowing the reaction to proceed to its steady state or completion much faster than it otherwise would; the enzyme remains unaltered by the completed reaction and can therefore continue catalysis. An immobilized enzyme is an enzyme attached to an inert, insoluble material-such as calcium alginate. This can provide increased resistance to changes in conditions such as pH or temperature. It also lets enzymes be held in place throughout the reaction, following which they are easily separated from the products and may be used again-a far more efficient process and so is widely used in industry for enzyme catalysed reactions. An alternative to enzyme immobilization is whole cell immobilization. Carrier matrices for enzyme immobilisation by adsorption and covalent binding must be chosen with care. The manufacture of high-valued products on a small scale may allow the use of relatively expensive supports and immobilisation techniques whereas these would not be economical in the large-scale production of low added-value materials. A substantial saving in costs occurs where the carrier may be regenerated after the useful lifetime of the immobilised enzyme. This book is simple protocols for the immobilization of enzymes and cells that could be useful for application at industrial scale, novel protocols for immobilization in the future, and new chemical reactors able to overcome the limitations of a number of immobilized derivatives.