Industrial use of enzymes

What are the benefits to using enzymes in industry?

The processes are highly efficient, enzymes obtained from micro-organisms, less energy is required, specific processes require specific enzymes, enzymes can be immobilisaed

What is an immobilised enzyme?

Bound to a surface so it cannot dissolve or move

What are the advantages of immobilising enzymes?

It reduces the cost as the enzyme can be reused, the enzyme is stabilised so can tolerate a wider range of temperatures and pHs, the enzyme and product are easily separated, continuous processing can take place, productivity is increased

What are the disadvantages of immobilising enzymes?

The enzyme may bind to the substrate with lower affinity (so will not be able to catalyse the reaction as effectively)

Types of immobilised enzymes

Adsorption (carrier bound), encapsulation (microencapsulation), covalent bonding (cross-linked), cellulose bound, entrapment (enzyme inclusion)

What does adsorption mean?

The enzyme is bound to the surface of a material

What does encapsulation mean?

The enzyme is placed within a partially permeable membrane or structure, like a polymer

What does covalent bonding mean?

The enzyme will be immobilised to a binding compound

What does cellulose-bound mean?

Entrapment within an insoluble particle and then cross-linked

What does entrapment mean?

The enzyme is placed within the internal structure of a silica gel lattice

What are the medical adaptations of immobilised enzymes?

Lactase, biosensors, biological washing powder, glucose isomerase, collagenase

What is the importance of lactase?

Lactose intolerant people cannot produce lactase in their pancreatic juice so cannot digest milk sugar (lactose) in their small intestine. With lactase, they are able to drink dairy products

What is the importance of glucose isomerase?

Produces fructose which is sweeter than glucose so less can be used to produce the same flavour, but with lower calories

What is the importance of collagenase?

Can be used in the collagen hydrolysis reaction to treat skin ulcers

What is the laboratory method to produce lactose free milk?

The immobilised lactase converts lactose into glucose and galactose as the milk flows through. The lactase has a small volume and a large surface area to volume ratio so effectively digests the lactose

Apparatus: substrate enters the top of a wide glass tube containing alginate pellets with immobilised enzyme (or microbe), and then flows through the tap (to regulate flow rate) to release the products at the bottom

What is a biosensor?

An analytical instrument converting a biological response into an electrical signal, used to detect specific substances or conditions by measuring values

What can biosensors measure?

Body temperature, blood pressure, pulse rate, oxygen tension, pH, glucose, enzymes, antibodies, presence of illegal drugs, presence of specific bacteria, cancers and specific DNA sequences

What are the parts of a biosensor?

Substrate - receptor, transducer, amplifier, processor, read out

What sample can be applied?

Bacteriological medium, blood, urine, pond water

How does the receptor work?

It can consist of living cells or tissues or immobilised enzymes or antibodies attached to a membrane

How does the transducer work?

Converts a chemical signal into an electrical signal

How does the amplifier work?

Boosts the electrical signal to enable the processor to convert the electrical signal into a reading or measurement

How is a biosensor calibrated?

Insert a calibration electrode into the test port before use. It should be periodically used to check the biosensor is working accurately