Spinning cloth disc reactor accelerates enzyme reactions

Researchers from the University of Bath have developed a new enzymatic process intensification technology - the ‘spinning cloth disc reactor’ (SCDR) - which is one of only a few technologies available for accelerating the rate of an enzyme reaction.

The SCDR was developed by Drs Emma Emanuelsson and Darrell Patterson in the university’s Department of Chemical Engineering. As described in the scientists’ research paper, the device is based on but extending the principles of the conventional spinning disc reactor (SDR), using “centrifugal forces to allow the spread of thin film across the spinning disc which has a cloth with immobilised enzyme”.

The SCDR therefore produces a flow of thin film both on top of, as well as through, the enzyme-immobilised cloth, providing a large interfacial surface area for the reaction. According to the scientists, “This geometry promotes accelerated reactions due to high mass transfer rates and rapid mixing.”

“Our work has shown that this system produces enhanced reaction rates compared to conventional enzyme reaction systems,” Dr Patterson said. “Our initial work has been on the conversion of a simple oil system (tributyrin hydrolysis), which shows us if the reactor could be used practically for the treatment of oily wastewaters, for example. We found that the conversion and reaction rates in the SCDR were significantly higher than that in a conventional batch stirred tank reactor under comparable conditions.”

Dr Emanuelsson added that while “many enzyme reactors suffer from a loss of enzyme activity over many cycles of reaction due to deactivation … the immobilised lipase showed excellent stability to repeat reactions in the SCDR: for the tributyrin system, 80% of the original lipase activity was retained after 15 consecutive runs”.

The team demonstrated the robustness of the SCDR to industry-relevant feeds through the successful hydrolysis of different vegetable oils at reaction rates five times higher than other reactors. Dr Patterson said the device was “also simple to control - disc/cloth spinning speed and reactor feed flow rate gave good control of reaction rate and conversion”.

A residence time distribution and flow analysis study showed that the SCDR is not quite like other rotating reactors, such as conventional spinning disc reactors and rotating packed bed reactors. Rather, said Dr Patterson, it is “a separate class of spinning disc-type reactor for process intensification. We have called this new reactor class ‘spinning mesh disc reactors’ (SMDRs), which enables any type of mesh (ie, not just cloths) with an unbound top surface on a spinning disc to be included within this new reactor classification”.

Dr Patterson said the concept can “readily be extended to other enzyme-catalysed reactions, where enhanced mass transfer and enzyme stability is needed”. The researchers are currently looking at applications in biodiesel synthesis and pharmaceutical reactions.