5 - Enzymes In Technology And Medical Applaicaionst Flashcards
1
Q
Sources of enzymes for food applications
A
- 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- increasingly these processes have been replaced by enzymes or enzyme mixtures produced in bioreactors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
2
Q
Proteases used in cheese production
- how they help make cheese
A
- ‘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
3
Q
How to produce chymosin (from rennet) in use for cheese production
A
- 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’
4
Q
Enzymes in the meat, leather and textile industries
A
- 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.
5
Q
Enzymes in starch processing
A
- 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
6
Q
Corn starch processing
A
(Arrows going down)
7
Q
How useful is the production of HFCS (High fructose corn syrup)
A
- found in many sweetened drinks and sweet products
- worth many billion pounds in America alone
8
Q
Enzyme production of aspartame = nutrasweet
A
- 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
9
Q
Uses of aspartame
A
- called E951
- main sweetener used in ‘diet’ drinks
10
Q
Thermolysin info
A
11
Q
Immobilised enzymes info
A
12
Q
Other enzymes in industry info
A
13
Q
Enzymes in environmental technologies
A
- 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)
14
Q
Manufacture of fine chemicals
A
15
Q
Synthesis of pharmaceuticals with enzymes
A
