Chemistry Reference
In-Depth Information
Comparing the effectiveness of different systems is, however, difficult since due
to mass transfer being a major limitation, the success of the system depends very
much on the size of the substrate used in testing the material [
2
]. As with the li-
pase examples, enzyme activity is reported in various ways, with only a few papers
determining kinetic parameters [
81
,
82
,
85
-
88
], and the majority making use of a
single-point estimation for a given condition. Different reporting methods are also
used for depicting enzyme stability.
4.5 Conclusion
Enzymes undoubtedly play a major role in industry, and their popularity is likely to
grow over coming years due to increasing demand for more environmentally friend-
ly and efficient processes. Many of the current methods of enzyme immobilisation
have significant drawbacks, such as greatly reducing enzyme activity, being costly
and time-consuming to prepare, and not having 'green' credentials due to materials
and conditions involved.
The bioinspired silica immobilisation routes outlined, however, aim to surmount
these challenges, with simple procedures, mild conditions, short preparation times
and the use of low cost additives. As a result, research and investment in this area
of enzyme immobilisation is likely to expand in the future. Moving forward, one
should note some of the issues with bioinspired silica for enzyme immobilisation.
Some of these challenges include the so far lack of any demonstrable control on
mass transport of substrate/product to and from the immobilised enzyme. This is-
sue perhaps can be tackled through silica chemistry by systematically tuning po-
rosities, particle sizes and morphologies of the support. Availability of complete
characterisation of immobilised enzymes—support properties as well as enzyme
kinetic parameters—has been poor in many reports, thereby hindering the process
of mechanistic and molecular level understanding. In order for the potential of this
technology to be commercially realised, investigations focussing on process devel-
opment would be of immense importance.
4.6 Acknowledgments
The authors acknowledge the financial support from the Department of Chemical
and Process Engineering, the Faculty of Engineering at University of Strathclyde,
the Royal Society (grant number TG090299) and The Carnegie Trust Vacation
Scholarship. SVP thanks Professor S. J. Clarson and his group for various helpful
discussions.
