Immobilised Enzymes Flashcards
Why use isolated enzymes over whole organisms?
-less wasteful
(organism biomass vs enzyme products)
-more efficient
(higher concentration of enzymes)
-more specific
(no wasteful side reactions)
-maximise efficiency
(optimum conditions for enzyme rather than organism)
-less downstream processing
(pure product formed)
Why use extracellular enzymes?
-easier to isolate
-secreted outside the cell
-microorganisms produce hundreds of intracellular enzymes making it harder to isolate specific enzymes
-more robust (evolved to cope with a wider range of conditions than intracellular enzymes have to withstand)
Sometimes use intracellular
-bigger range of them
What does immobilised enzymes involve?
-attaching enzymes to an inert, insoluble surface
What do I.E allow to do?
-more easily recovered and re-used
Surface immobilisation
-through absorption
-through covalent or ionic bonding
Entrapment
-in a gel matrix
-behind a partially permeable membrane
Encapsulation in a microcapsule
Advantages
-can be reused-cheaper
-easily separated from reactants and products they are catalysing so reduced downstream processing-cheaper
-more reliable-higher degree of control over process as insoluble support provides stable microenvironment for the immobilised enzymes
-greater temp tolerance-less easily denatured by heat and work at optimum levels over a much wider range of temperatures, making bioreactor less expensive to run
-ease of manipulation-catalytic properties can be altered to fir a particular process more easily than those of free enzymes
Disadvantages
-reduced efficiency-reduce its activity rate
-higher initial costs of materials-immobilised enzymes are more expensive than free enzymes or microorganisms, however not replaced frequently
-higher initial costs of bioreactor-different system needed from traditional fermenters so initial investment cost
-more technical issues-reactors which use immobilised enzymes are more complex than simple fermenters-more things that can go wrong
Immobilised penicillin acylase
-used to make semi-synthetic penicillin from naturally produced penicillin
-many bacteria still vulnerable to this so very important in treating infections caused by bacteria resistant to original
Immobilised glucose isomerase
-produce fructose from glucose
-used as sweetener
-glucose is produced cheaply then enzyme is used to turn into marketable fructose
Immobilised lactase
-produce lactose-free milk
-good for those with intolerance
Immobilised aminoacylase
-pure samples of L-amino acids used in production of pharmaceuticals, organic chemicals, cosmetics , and food.
Immobilised glucoamylase
-to complete breakdown of starch to glucose syrup
-amylase enzymes break starch down into short chain polymers called dextrins
-breakdown to glucose is catalysed by
