22 - Cloning/Biotech Part 2

Question 1

Isolated enzymes efficiency

Answer 1

Less wasteful than whole enzymes as whole microorganisms use up more substrate + they work at higher concentration than possible in a cell

Question 2

Isolated enzymes artificial

Answer 2

Maximise efficiency - isolated enzymes can be given ideal conditions for maximum product formation

Question 3

Isolated enzymes waste

Answer 3

More specific as no unwanted enzymes are present so no wasteful side reactions

Question 4

What is downstream processing?

Answer 4

Series of steps to purify a sample/extract products - whole microorganisms gives a variety of products making isolation harder!!!

Question 5

Extracellular > Intracellular

Answer 5

When secreted, extracellular enzymes are easier to isolate and cells produce a few of extracellular enzymes but a range of intracellular enzymes (processing)

Question 6

Robust IE OR EE

Answer 6

EE as conditions outside cell less controlled so adapted to greater variations in temp and ph than ie

Question 7

When are IE used?

Answer 7

Bigger range of IE so in some cases its ideal

Question 8

Disadvantage of EE

Answer 8

Expensive extraction/isolation process and need for tightly controlled conditions

Question 9

Example of IE used in industry

Answer 9

Penicillin acylase for converting penicillin into drugs which are more effective

Question 10

Why are enzymes immobilised?

Answer 10

As free enzymes are often very wasteful - because they are now held in place they can be recovered from the reaction mixture and reused time after time - enzymes do not contaminate thus less downstream processing = economical

Question 11

Advantage of immobilised enzymes

Answer 11

Reused hence cheaper
Less downstream processing can easily separate/no contaminate
More reliable = more control over environment
Greater temperature tolerance - less easily denatured

Question 12

Immobilised enzymes Ease of manipulation??

Answer 12

Catalytic properties can be altered to fit a particular process - immobilised glucose isomerase can be continuously used for over 1000 hours ; keeps costs low

Question 13

Disadvantage of immobilised enzymes

Answer 13

Reduced efficiency - may reduce its activity rate
HIGHER INITIAL COSTS OF BIOREACTOR BUT ENZYMES DO NOT NEED REPLACING
More technical issues

Question 14

4 methods of immobilised enzymes

Answer 14

Adsorption to inorganic carriers
Covalent/ionic bonding
Entrapment in matrix
Membrane entrapment

Question 15

Adsorption to inorganic carriers

Answer 15

Very simple and cheap/enzymes accessible to substrate BUT enzymes can be lost from matrix

Question 16

Surface immobilisation covalent/ionic

Answer 16

Cost varies/enzymes strongly bound - ph has little effect on activity BUT active site may be modified in process so less effective

Question 17

Entrapment in gelatin/polysaccharides

Answer 17

Widely applicable to different processes BUT may be expensive/difficult to entrap/diffusion of substrate can be slow and hold up activity

Question 18

Membrane entrapment

Answer 18

Simple and small effect on enzyme activity BUT relatively expensive and can hold up rate of reaction with slow substrate diffusion

Question 19

Microorganisms need

Answer 19

Food/oxygen and a carefully controlled environment

Question 20

Penicillin acylase

Answer 20

Semi synthetic penicillins from naturally producing penicillins - many bacteria still vulnerable even with antibiotic resustance

Question 21

Immobilised glucose isomerase

Answer 21

Fructose made from glucose - much sweeter than sucrose or glucose and is widely used as a sweetener

Question 22

Lactase

Answer 22

Produces lactose-free milk ; hydrolyses lactose to glucose and galactose for some people/cats are intolerant of lactose

Question 23

Aminoacylase

Answer 23

Produces L-amino acids for pharmaceuticals

Question 24

Glucoamylase

Answer 24

Breakdown of starch to glucose syrup (dextrins to glucose)

Question 25

Nitrile hydratase

Answer 25

Allows hydration of acrylonitrile to acrylamide - without using suphuric acid/reduced copper catalyst but conditions needed were extreme (yield is poor and unwanted by products were formed)