Chemistry Reference
In-Depth Information
Fig. 4.2
Schematic representation of enzyme and carrier properties that influence the performance
of immobilised enzymes. Figure reproduced from ref. [
12
] with permission from Elsevier
4.3
Immobilisation Techniques
This section considers each immobilisation technique in further details and com-
pares with other existing methods. Although each approach has been adopted for a
range of enzymes, for a clearer illustration and comparison, we have chosen lipase
as an example enzyme. It is therefore important to outline key information of li-
pases such as properties and performance in biocatalysis prior to discussing their
immobilisation. Before we discuss properties of lipase, we briefly present typical
protocols used for measuring and comparing enzymatic activity.
4.3.1
Evaluation and Comparison of Biocatalyst Performance
There are many possible ways to evaluate and compare free and immobilised en-
zyme performance in terms of activity and stability, and this therefore makes direct
comparisons between systems difficult at times. Therefore, it is often necessary to
make qualitative, rather than quantitative comparisons.
To evaluate enzyme activity, a common approach is to measure the amount of
product formed (or rate) over a fixed time duration and compare this between the
free and immobilised systems. Another approach is to compare the enzyme kinetic
parameters such as the maximum reaction rate (
V
max
), Michalis-Menton constant
