Using immobilised enzymes
Isolated enzymes
Advantages
Less wasteful – whole organisms use up substrate growing/reproducing producing
biomass not product
More efficient – work at higher conc than poss when part of whole microorganism
More specific – no unwanted enzymes = no wasteful side reactions
Maximise efficiency – can be given ideal conditions for max product formation that
may differ from those needed for growth of whole microorganism
Less downstream processing – pure product produced, whole microorganism give
variety of products
Extracellular enzymes
Most isolated enzymes used are extracellular produced by microorganisms
o Easier + cheaper to use than intracellular
Extracellular are secreted = easier to isolate + use
Microorganism produces few extracellular = easier to identify + isolate required 1
Extracellular more robust than intracellular
o Conditions outside cell less tightly controlled than in cytoplasm
o Extracellular adapted to cope with greater variations in temp + pH
Sometimes intracellular used due to bigger range – benefits of used very specific
intracellular outweigh disadvantages of more expensive extraction + isolation
process + need for tightly controlled conditions
Examples of intracellular inc penicillin acylase – convert penicillin into semi-synthetic
drugs that are more effective
Immobilised enzymes
Using free enzymes = wasteful
Immobilised – attached to inert support system over which substrate passes +
converted to product
o Mimicking nature – enzymes in cells bound to membranes
Immobilised – held stationary = can be recovered from reaction mixture + reused
Advantages of immobilised enzymes
Reused = cheaper
Easily separated from reactants + products = reduced downstream processing =
cheaper
More reliable – more control over process as insoluble support provides stable
microenvironment for im enzymes
Greater temp tolerance – less easily denatured by heat + work at optimum levels
over wider range of temp = bioreactor less expensive to run
Ease of manipulation – catalytic properties of the enzymes altered to fir particular
process more easily than free enzymes
o E.g. enzymes can be continuously used = keep bioreactor running for long
period without emptying/cleaning= running costs low
Disadvantages of immobilised enzymes
Reduced efficiency – process of immobilising enzyme may reduce its activity rate
Higher initial costs of materials – more expensive then free enzymes/microorganisms
o But don’t need to be replaced frequently
Isolated enzymes
Advantages
Less wasteful – whole organisms use up substrate growing/reproducing producing
biomass not product
More efficient – work at higher conc than poss when part of whole microorganism
More specific – no unwanted enzymes = no wasteful side reactions
Maximise efficiency – can be given ideal conditions for max product formation that
may differ from those needed for growth of whole microorganism
Less downstream processing – pure product produced, whole microorganism give
variety of products
Extracellular enzymes
Most isolated enzymes used are extracellular produced by microorganisms
o Easier + cheaper to use than intracellular
Extracellular are secreted = easier to isolate + use
Microorganism produces few extracellular = easier to identify + isolate required 1
Extracellular more robust than intracellular
o Conditions outside cell less tightly controlled than in cytoplasm
o Extracellular adapted to cope with greater variations in temp + pH
Sometimes intracellular used due to bigger range – benefits of used very specific
intracellular outweigh disadvantages of more expensive extraction + isolation
process + need for tightly controlled conditions
Examples of intracellular inc penicillin acylase – convert penicillin into semi-synthetic
drugs that are more effective
Immobilised enzymes
Using free enzymes = wasteful
Immobilised – attached to inert support system over which substrate passes +
converted to product
o Mimicking nature – enzymes in cells bound to membranes
Immobilised – held stationary = can be recovered from reaction mixture + reused
Advantages of immobilised enzymes
Reused = cheaper
Easily separated from reactants + products = reduced downstream processing =
cheaper
More reliable – more control over process as insoluble support provides stable
microenvironment for im enzymes
Greater temp tolerance – less easily denatured by heat + work at optimum levels
over wider range of temp = bioreactor less expensive to run
Ease of manipulation – catalytic properties of the enzymes altered to fir particular
process more easily than free enzymes
o E.g. enzymes can be continuously used = keep bioreactor running for long
period without emptying/cleaning= running costs low
Disadvantages of immobilised enzymes
Reduced efficiency – process of immobilising enzyme may reduce its activity rate
Higher initial costs of materials – more expensive then free enzymes/microorganisms
o But don’t need to be replaced frequently
