6.4.14 Immobilised Enzymes in Biotechnology Flashcards
What is an immobilised enzyme?
An immobilised enzyme is an enzyme that is attached to an insoluble material to prevent mixing with the product
Enzymes can be immobilised in several ways:
Attached to an inert substance
Enclosed in a capsule
Contained within a partially permeable membrane
Enzymes are often immobilised for use in industrial processes as it means the enzyme can be reused in future processes rather than being discarded after it has been used once
Reusing the enzyme also avoids the need to separate the enzyme from the product in downstream processing
The immobilised enzymes are contained within a column through which the substrate is filtered in solution
As the substrate runs through the column, enzyme-substrate complexes are formed and products are produced
These products then flow out of the column, leaving the enzymes behind to catalyse the reaction again
What are the advantages of an immobilised enzyme?
There is no enzyme in the product (the product is uncontaminated) and therefore there is no need to further process or filter the end product
The immobilised enzyme can be reused multiple times which is both efficient and cost-effective (enzymes are expensive)
Immobilised enzymes have a greater tolerance of temperature and pH changes (immobilisation often makes enzymes more stable)
What are the disadvantages of immobilised enzymes?
Specialist expensive equipment is required
Immobilised enzymes are more costly to buy, so are unlikely to be financially worthwhile for smaller industries
The rate of reaction is sometimes lower when using immobilised enzymes as the enzymes cannot freely mix with the substrate
What is the use of immobilised enzymes in industry?
There are many industrial and medical applications of immobilised enzymes, including production of the following:
Lactose-free dairy products such as milk
Enzyme: Lactase
Converts lactose to glucose and galactose
Semi-synthetic penicillin which overcomes issues of penicillin resistance
Enzyme: Penicillin acylase
Converts the original form of penicillin into one which is effective against penicillin-resistant organisms
Glucose products used to sweeten and thicken foods
Enzyme: Glucoamylase
Converts starch and other dextrins into glucose
Fructose for sweetening of foods where a lower quantity of sugar is necessary
Enzyme: Glucose isomerase
Converts glucose into the sweeter sugar, fructose
Purified samples of L-amino acids used in food production
Enzyme: Aminoacylase
Separates out L-amino acids from D-amino acids
Acrylamide required in disposable nappy production
Enzyme: Nitrilase
Converts acrylonitrile into acrylamide
Why is lactose-free milk production important?
Milk is a valuable source of nutrients containing protein, fat and the carbohydrate lactose
5-10% of the UK population are lactose intolerant
Lactose is a disaccharide that is broken down into glucose and galactose
