5 - Enzymes In Technology And Medical Applaicaionst

Question 1

Sources of enzymes for food applications

Answer 1

• traditional food bio-processing involves intact microbes naturally present in food environment
• ‘fermentations’ by e.g. lactobacilli, etc.
• increasingly these processes have been replaced by enzymes or enzyme mixtures produced in bioreactors
• e.g. cheese-production, rennet etc.
• now many new enzyme-based food processes - make for big business

Question 2

Proteases used in cheese production
- how they help make cheese

Answer 2

• ‘rennet’ a mixture of enzymes from the stomach unweaned calves
• but chymosin is the active aspartyl protease which digests casein, the major milk protein
• digestion of casein destabilises fat droplets so milk clots
• this separates curds and whey; first step in making cheese

Question 3

How to produce chymosin (from rennet) in use for cheese production

Answer 3

• Clone the gene encoding the enzyme and express it in bacteria or fungi
  –Grow the modified bacteria/fungi in biofermentors
  –Purify the protein
  –Some fungal and plant proteases have similar activity to chymosin
  –These can be used for ‘vegetarian cheese’

Question 4

Enzymes in the meat, leather and textile industries

Answer 4

• proteases used to treat animal hides to remove their hair and soften skin
• proteases can be used to ‘tenderise’ meat
• celluloses used to treat denim to generate ‘stone-washed’ texture and look on different materials
• preferred enzymes are plant thiol proteinases from various fruits, bromelain (from pineapple), etc.

Question 5

Enzymes in starch processing

Answer 5

• high volume conversion of starch to glucose syrups uses bacterial amylases and amylo-glucosidases
• since 1970s, high fructose syrups - have been made by using glucose isomerase (a bacterial enzyme)
• high fructose corn syrup (HFCS) is very sweet and now very cheap, compared to sugar

Question 6

Corn starch processing

Answer 6

(Arrows going down)

Question 7

How useful is the production of HFCS (High fructose corn syrup)

Answer 7

• found in many sweetened drinks and sweet products
• worth many billion pounds in America alone

Question 8

Enzyme production of aspartame = nutrasweet

Answer 8

• Aspartame is L-Asp-L-Phe-OMe i.e. it is a dipeptide O-methyl ester
• made of 2 amino acids (dipeptide) - aspartic acid and phenylalanine
• D- specific degradation enzymes are used to produce pure L-amino acids from racemic mixtures
• Peptidase Thermolysin is used ‘in reverse’ to form the dipeptide

Question 9

Uses of aspartame

Answer 9

• called E951
• main sweetener used in ‘diet’ drinks

Question 10

Thermolysin info

Question 11

Immobilised enzymes info

Question 12

Other enzymes in industry info

Question 13

Enzymes in environmental technologies

Answer 13

• lipases used to degrade fatty deposits and clear drains
• fungal and bacterial celluloses and lignin peroxidases can break down plant biomass to ‘fermentable sugars’
• other enzymes can convert biomass to ethanol; used in biofuels and ‘bio refineries’
• enzymes used in degradation of wastewater pollutants and in ‘bioremediation’

(Microorganisms still preferred for most of these applications though)

Question 14

Manufacture of fine chemicals

Question 15

Synthesis of pharmaceuticals with enzymes

Question 16

Enzymes in biosensors and blood testing kits

Answer 16

• biosensors are (electronic) analytical devices giving direct read-outs
• most biosensors based on enzymes
• simple enzyme-based devices common,y used for diabetics in testing and monitoring blood-glucose levels and cholesterol levels

Question 17

Different biosensor designs and detection principles

Question 18

Enzymatic biosensors based upon oxidases

Question 19

Other applications of enzymes in diagnosis

Question 20

Use of enzymes in diagnosing strokes

Answer 20

• during a stroke, purines released into the blood
• …

Question 21

Use of enzymes as therapeutics

Answer 21

…