Unit 6 – Investigative Project:
Investigation of Effects of Starch Concentration on Immobilised Amylase Enzyme
Name: ***
Project supervisor: ***
, Emily Bullas - 246413 Unit 6 Assingment AB
Section 1: Literature Review
Enzymes are proteins which increase the rate of chemical reactions within the body. (Cleaveland
Clinic, 2021). They do this by lowering the amount of energy needed for the reaction to begin - the
activation energy (Kahn Academy, 2019). They occur naturally in all living beings, but can also be
used in the manufacture of food and other products (Cleavland Clinic, 2021). Their activity can be
affected by many different factors such as temperature, pH, concentration of enzymes and
substrates, and more (Kahn Academy, 2019). Each enzyme has its own optimal conditions under
which it works best, and too far outside of these conditions the enzymes will no longer work. This is
because the active site, the area which binds to the substrate, changes shape or ‘denatures’ when it
is too far beyond its optimal conditions (Kahn Academy, 2019).
Enzyme immobilisation is the process of physically confining or localising enzymes in a defined
region of space, retaining their catalytic activities, which can be used repeatedly and continuously
(Brena et al, 2013). There are three main techniques for immobilising enzymes, adsorption, binding
and entrapment. Adsorption involves enzymes binding onto inert carriers such as silica and clay,
using hydrogen bonds and van der walls forces; these weak forces which bind the enzymes to the
carrier mean that the enzyme activity is not affected, though other factors such as pH, temperature
and ionic strength may affect binding (QBB, 2021). The binding method can be divided into two
categories, ionic binding and covalent binding. Ionic binding is carried out using ion exchange resins,
materials with positive or negative charges, allowing them to bind to enzymes with the opposite
charge, for example DEAE cellulose (positive charge) and CM cellulose (negative charge) (QBB,
2021). Covalent binding works through the formation of covalent bonds between functional groups
of enzymes and functional groups of carriers (QBB, 2021). Finally, the entrapment method works by
physically trapping the enzyme within a material such as agarose or alginate (QBB, 2021).
The applications of enzyme immobilisation are far-reaching, due to the different methods which are
possible and the variety different enzymes which are available. In the biomedical industry,
immobilised enzymes are widely used for diagnosing and treating diseases and for drug delivery
systems (Bera, 2023). These techniques are also used in the production of a variety of products such
as amino acids, antibiotics, beverages and vegetable oil-based biodiesel (Bera, 2023). It can also be
used in the treatment of sewage and industrial effluents in wastewater management, and much
more (Bera, 2023). While the applications of enzyme immobilisation are important, the specifics are
not particularly important for this project.
Immobilised enzymes have many advantages over free enzymes in solution; they are more robust
and resistant to environmental changes, more easily recovered to be reused, and allow for a greater
variety of bioreactor designs (Homaei et al, 2013). Furthermore, after the initial investment,
immobilised enzymes save in capital costs and improve the stable supply of products in the market
(EBC, 2023). Enzyme immobilisation improves research and industrial processes by improving
process control, reducing the chance of product contamination, reducing the labour input needed
and improving the stability of products (EBC, 2023).
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