for chemical eng

1. ENZYME IMMOBLIZATION
• INTRODUCTION
• Enzyme are large biological molecules responsible for the thousands of metabolic processes that
sustain life.
• Since enzyme are not stable and they can not be recovered for reuse.
• DEFINATION :
• “Immobilization of enzyme (or cells) refer to the technique of confining anchoring the enzyme
in on an inert support for their stability and function reuse”

2. PROPERTIES
• The material used for enzyme immobilization called carrier matrices .
• The ideal carrier matrix has the following properties are:
• Low costs
• Inert less
• Physical strength
• Regenerability after use

3. IMMOBILIZATION TECHNIQUES
• Immobilization techniques can be classified by basically two methods, the
chemical and the physical method. The former is covalent bond formation
dependent .
• The two Method consist of :
• Chemical method consist of Covalent binding, Cross linking
• Physical method consist of Adsorption, Entrapment:

4. METHODS OR TECHNIQUES
• ADSORPTION
• ENTRAPMENT
• COVALENT BINDING
• CROSS LINKING

5. ADSORPTION
• Adsorption involves the physical binding of enzyme (or cells) on the surface of an inert support.
• The support material may be inorganic (e.g. alumina ,silica gel ,calcium) or organic ( starch,
carboxymethyl,cellulose ).
• Adsorption of enzyme molecules involves weak forces such as Vander Waals forces and
hydrogen bonds.
• Therefore ,the adsorbed enzyme can be easily removed by minor changes in pH, ionic strength
or Temperature.

6. ADVANTAGES & DISADVANTAGES
• Advantages
• 1.The procedure of immobilization is simple.
• 2. It is possible to separate and purify the enzymes while being immobilized.
• 3. The enzymes are not usually deactivated by adsorption.
• 4. The adsorption is a reversible process.
• Disadvantages
• 1. The bonding strength is weak.
• 2. The state of immobilization is very sensitive to solution pH, ionic strength, and temperature.
• 3. The amount of enzymes loaded on a unit amount of support is usually low.

8. ENTRAPMENT
• Enzymes can be entrapped within cross-linked polymers by forming a highly cross-linked network of polymer in
the presence of an enzyme.
• This method has a major advantage in the fact that there is no chemical modification of the enzyme, therefore, the
intrinsic properties of an enzyme are not altered.
• However, the enzyme may be deactivated during the gel formation. Enzyme leakage is also a problem. The most
commonly employed crosslinked polymer is the polyacrylamide gel system.
• This has been used to immobilize alcohol dehydrogenase, glucose oxidase, amino acid oxidase, hexokmase,
glucose isomerase, urease, and many other enzymes.

9. ENZYME CAN BE ENTRAPPED
BY SEVERAL WAYS :
• 1.Enzyme inclusion in gels.
• 2.Enzyme inclusion in fibers.
• 3.Enzyme inclusion in microcapsules

10. COVALENT BINDING
• Immobilization of the enzyme can be achieved by creation covalent bonds between the chemical
groups of enzyme and chemical groups of the support.
• The following are the common methods of covalent binding:
• 1.cyanogen bromide activation
• 2.Diazotation
• 3.Peptide bonds formation
• 4.Activation by Bi or polyfunctional regents

11. CROSS –LINKING
• The absence of a solid support is a characteristics feature of immobilization of enzymes by
cross-linking.
• The enzyme molecules are immobilized by creating cross-links between them , through the
involvement of poly-functional reagent.
• These reagent in fact react with the enzyme molecules and create brides which form the
backbone to hold enzyme molecules.
• Glutaraldehyde is the most extensively used cross-linking reagent

12. EFFECT OF IMMOBILIZATION ON ENZYME PROPERTIES
• Enzyme immobilization is frequently associated with alterations in enzyme properties
,particularly the kinetic properties of enzyme some are listed below:
• There is substantial decrease in the enzyme specificity . This may be due to conformational
changes that occur when the enzyme gets immobilized.
• The kinetic constants km and V max of an immobilization enzyme differ from that of the native
enzyme .This is because the conformational changes of the enzyme will affect the affinity
between enzyme and substrate.

13. • APPLICAION OF IMMOBILIZED ENZYMES AND
CELLS
• INDUSTRIAL USES
• ANALYTICAL
• THERAPEUTIC