Question

Cross-linking method of immobilization is also known as
A. Entrapment
B. Copolymerization
C. Encapsulation
D. Adsorption

Answer 1

Immobilized enzyme is an enzyme which is attached to an inert, insoluble material like calcium alginate. It is produced by reacting a mixture of sodium alginate and an enzyme solution with calcium chloride. This process provides increased resistance to changes in physical conditions such as pH or temperature.

Complete step by step answer:
A copolymer is formed when two different kinds of monomers polymerize together to give a compound containing both parent monomers. This process is called copolymerization. In this process, the cross-linking of two different monomers takes place. The enzyme immobilization can be done by the condensation copolymerization method.
A cross-linked enzyme aggregate is an immobilized enzyme which is prepared by cross-linking the physical enzyme aggregates with a difunctional cross-linker. It can also be used as stereoselective industrial biocatalysts.
Altus Biologics in the 1990s pioneered the use of cross-linked enzyme crystals (CLECs) as industrial biocatalysts. CLECs are significantly more stable to denaturation by heat and organic solvents, and proteolysis than any corresponding soluble enzyme or lyophilized or freeze-dried powder. Cross-Linked Enzyme Crystals are robust and highly active immobilized enzymes of particle size varying from 1 to 100 micrometre. The operational stability and ease of recycling, along with high catalyst and volumetric productivities of these crystals, makes them ideal for industrial biotransformations.

So, the correct answer is option B.

Additional Information:
A few applications of CLEAs are:
1.In the synthesis of pharmaceuticals, agrochemicals, flavours and fragrances, nutraceuticals, bulk monomers, fine chemicals, and biofuels.
2.In animal feed, like phytase for utilization of organically bound phosphate by pigs and poultry.
3.In food and beverage processing, like lipases in cheese manufacture and laccase in wine clarification.
4.In cosmetics, like in skincare products
5.In oils and fats processing, like in biolubricants, bioemulsifiers, bio emollients.
6.In carbohydrate processing, like laccase in carbohydrate oxidations.

Note:
Cross-Linked Enzyme Crystals are very useful biocatalysts due to their simplistic, inexpensive and effective method of production. They can be reused and have improved stability and performance. This method applies to any enzyme, including the cofactor dependent oxidoreductases. Application of CLECs to penicillin acylase in antibiotic synthesis showed immense advantages over other biocatalysts.