Immobalised Enzmes. Flashcards
(13 cards)
What are the advantages of using isolated enzymes over using the whole organism for industry?
1- less wasteful -> whole organisms need nutrients for survival and growth -> isolated enzymes don’t.
2- More efficient -> it can work at high concentrations than they do inside organisms.
3- More specific -> only chosen enzyme used -> no mixture like in whole organism -> chosen reaction catalysed.
4- less “downstream processing” -> cheaper -> isolated procedure produces 1 pure product -> whole organisms produce many products which need separating.
What type of enzyme are most isolated enzymes and whys this an advantage?
- extracellular (secreted outside of cell)
- easier and cheaper than intracellular as it is more expensive to isolate and extract
- Each microbe produces few extracellular enzyme, making it easy to identify and isolate required enzyme. Whole organisms produce lots of intracellular enzymes which need extracting for cell and separating.
- Extracellular adapted to cope with greater variations of in temp and pH than intracellular.
What is the problem with isolated enzymes?
Still wasteful as enzyme and product are mixed up at the end.
What enzymes are better than isolated enzymes and what are they?
Immobilised enzymes better = enzymes that have been removed from organisms and are immobilised so they can’t move freely.
What is adsorption and advantage and disadvantage?
Adsorption - starch, clay attached by H / ionic bonds.
+ -> no change to shape of enzyme.
- -> weakly attached -> enzymes can detach.
Covalent bonding positive and negative.
Covalent -> attached to cellulose/gelatin
+ -> strong bonds -> enzymes won’t detach
- -> active some can be changed
What is entrapment ad and disadvantage?
Entrapment -> trapped inside porous matrix.
Ad-> cheap and easy no change to active site shape.
Dis -> enzyme molecules could leak out of matrix.
What is encapsulation ad and dis?
Encapsulation - trapped inside membrane capsule
+ = cheap and easy large amount of enzyme could be trapped.
- = only small substrate molecules can cross molecule.
What is cross linking ad and dis?
Cross linking = enzymes linked together by covalent bonds
+ = cheap and easy
- = may change A.S shape.
Method of enzyme immbolization technique.
1- substrate flows past fixed, immobilised enzyme.
2- E and S make contact -> reaction is catalysed.
3- product released with no enzyme mixed with it.
4- in encapsulation/entrapment - substrate has to diffuse into trapped enzyme inside matrix/membrane -> reaction occurs inside -> product diffuses back out.
Advantages of immobilised enzymes.
+ -> reusable -> cheaper.
+ -> decrease in downstream processing -> cheaper -> product not mixed with enzyme -> don’t have to separate.
+ -> high temp tolerance -> less likely to denature at high temp.
+ -> continuous process -> bioreactor kept running for long time without need for cleaning and emptying -> cheaper.
Disadvantages of immobilised enzymes.
- higher initial cosy -> IM enzyme more expensive.
- technical issues with complex bioreactor -> more goes wrong -> highly trained staff.
Examples of IE in industrial processes.
Lactose -> glucose and galactose (enzyme lactase) -> hydrolysis -> lactose free milk and dairy products.
Fructose -> sweetener (sweeter than glucose) -> less sugar needed to have same sweetness level enzyme: isomerase glucose -> fructose
Semi-synthetic penicillins -> save bacteria anti-biotic resistant -> have same antibiotic properties as natural -> effective against penicillin resistant organisms.
Enzyme: immobilised penicillin acylase.
