Enzyme Immobilisation Breakthrough Promises Major Savings For Industry
Researchers at The University of Auckland's School of Engineering are seeking commercial partners for a new process
that promises to slash the cost of common industrial processes involving the use of enzymes.
Uses range from producing milk products that overcome lactose intolerance through to the beer brewing process and such
new applications as applying anti-biotics to bandages.
The newly patented enzyme immobilising technology is co-invented by a PhD student, Mr. Quinn Zhou, who is a biochemical
engineer, and Professor Xiao Dong Chen. The work has been conducted in a team led by Professor Chen at the University's
School of Engineering. Professor Chen's contributions to food manufacturing research and development were recognised
recently when he was granted the rare honour of a personal chair in the Department of Chemical and Materials
Engineering, and he currently leads the establishment of the University's food and bio-product processing centre.
The new technology offers to solve a common problem in industrial processes where an enzyme is introduced to cause a
chemical change in a product.
"In most cases, these processes mix the product and the enzymatic compound together until the desired chemical change
has occurred," said Professor Chen. "The enzyme must then be 'turned off', even though it may have several more days of
productive potential. "
"Under these traditional methods, freely suspended enzymes are used for the reaction, incurring high costs in making
such products due to the complete loss of the enzyme after each conversion run. "
"In the case of milk products, the enzyme is neutralised by heating the milk, which has already had to go through a
condensing process in order to reduce the number or the size of vats required for the process to occur."
Professor Chen's work could replace them in a new plant installation with a device akin to large computer ink cartridge
containing enzyme particles effectively attached to a fibrous core.
In the case of milk processing, unadulterated whole milk can be exposed to the enzyme by passing it straight through the
enzyme immobilising 'cartridge', which continues to function for as long as the enzyme remains naturally active and
below the acceptable level of microbial contamination.
"We are able to show substantial cost savings from the process," said Professor Chen. "In the case of milk processing,
we calculate savings of around half a million dollars on a production run of six tonnes of liquid raw milk per hour - a
relatively small throughput by New Zealand dairy industry standards ".
"This does not include savings from other energy related issues like mixing and heating of the concentrated milk."
The search for commercially applicable methods of enzyme immobilisation is far from new, because the process is common
to a wide range of food and other industrial processes.
"The international significance of our discoveries is that we believe we have overcome the high costs associated with
various existing forms of enzyme immobilisation and still obtained high efficiency," said Professor Chen.
The key to this success has been the years spent researching how to produce particles from a liquid solution of enzyme
and then working out how to deposit those particles on the cartridge fibre to produce very high surface area per unit of
volume processed. Professor Chen's team expects to continue improving the efficiency of the process.
While the process has obvious appeal in areas such as milk and beer production (which is currently being explored in
conjunction with Dr. Matt Hardin who joined the team recently as a Lecturer of Biochemical Engineering at the same
department), Professor Dong believes its greatest potential lies in "small scale, high value applications, especially
where the process involves a high value enzyme and a high value product".
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