Enzymes (for example, those derived from bacteria) can convert a wide variety of starting materials into a wealth of target products. So-called white biotechnology aims at harnessing this ability to produce chemicals in an eco-friendly way. Since it sometimes takes several catalysts and steps to produce the desired product, Dirk Tischler's team designed a cascade for flow catalysis, in cooperation with groups from the Delft University of Technology, the Technical University Bergakademie Freiberg, and the Silesian University of Technology.
Dirk Tischler said, the starting materials glucose and glucose-1-phosphate (activated form) and UTP (uridine triphosphate, a biochemical energy carrier) were thus converted into trehalose in two steps that took place on immobilized enzymes. The first enzyme has the task of activating the glucose molecules, the second links them together. Since one enzyme requires different working conditions than the other, we immobilized them in two sequential reactors. This enables the researchers, for example, to adjust the temperature or the residence time of the substrates in the reactor independently of each other. It would also be conceivable not only to link sugars together using this method but also, for example, to grow medicinal agents on sugar, such as antibiotics casting a glance into the future.
In a follow-up project, which he funded together with the company Hirsch Engineering Solutions and which is supported by the Federal Ministry for Economic Affairs and Energy, he now focuses on optimizing the cascade. The goal is, first of all, to improve the substrate materials for the enzymes.
Tischler said, the silicate substrates we have been using so far are not equally well tolerated by all enzymes.
Moreover, they are often not reusable. Plastics, including those from biological sources, might be more suitable and can be molded by 3D printing. They have already proven their biocompatibility in various medical applications, points out the scientist.
Secondly, the project partners also want to make the enzyme cascade more cost-efficient by adding a kinase that recycles the separated UDP into UTP at the end of the reaction with the help of polyphosphate. As a result, the cascade can start anew.
Dirk Tischler said, until now, we have always had to add new UTP to start the cascade, which is fairly expensive. If we were able to recycle it by means of polyphosphate, the costs would be considerably reduced.
Journal Information: Daria Kowalczykiewicz et al, Engineering of continuous bienzymatic cascade process using monolithic microreactors – In flow synthesis of trehalose, Chemical Engineering Journal (2021). DOI: 10.1016/j.cej.2021.131439