Biocatalysis is playing a major role in the transition toward sustainable production. Transaminases are enzymes that enable the stereoselective production of amines and are a good alternative to traditional chemical synthesis and chiral resolution. In the past wider implementation of amine transaminases in industry has been hampered by poor operational stability, low recovered activity of immobilised enzyme and the need to add the cofactor pyridoxal-5'-phosphate to the reaction mixture.
In recent years protein engineering has enabled the expression of highly stable transaminases with exceptional affinity for the cofactor. Furthermore, microfluidics-based crosslinked enzyme aggregate preparation offers a promising way of using enzymes in continuous biocatalytic processes.
In the present work we look at the effect of exogenous PLP addition on the recovered activity and stability of CLEA particles prepared with the selected ATA. We determined the size and shape of microfluidicaly prepared particles with dynamic light scattering and electron microscopy. We also measured the activity and stability of the prepared CLEA particles in a continuous biocatalytic process in a membrane microreactor, with and without exogenous PLP in the feed flow.
The results show the chosen amine transaminase exhibits a high affinity for the cofactor PLP, and high recovered activities of CLEA particles prepared with the enzyme even in absence of exogenously added cofactor. We also confirmed this in the membrane microreactor process with immobilised CLEA particles, where we saw no significant differences in reactant conversion in the microreactor eluate, while it was operating with or without exogenous PLP in the reactor feed.
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