An Immobilised Silicon‐Carbon Bond‐Forming Enzyme for Anaerobic Flow Biocatalysis

The recent development of tailored cytochrome enzymes has enabled “new-to-nature” reactivities, such as the biocatalytic formation of carbon-silicon bonds using the cytochrome c from Rhodothermus marinus. To maximise the potential of this remarkable biocatalyst by increasing its turnover numbers (TON) and to enable its reusability in continuous processes, we report the use of the SpyTag/SpyCatcher bioconjugation system to immobilise this enzyme. We successfully modified the enzyme with a SpyTag without significant effects on its catalytic activity. Even after immobilization on microparticles the enzyme retained 60 % activity. When the immobilized enzyme was used in sequential batch or continuous flow to produce an organosilicon, we observed up to 6-fold higher turnover numbers over a total period of 10 days compared to the free enzyme reaction, however we observed a drop in stereoselectivity under these conditions. This is the first report on the successful immobilisation of a carbon-silicon bond forming enzyme for the continuous, biocatalytic production of organosilicons.