Artificial light-harvesting complexes enable Rieske oxygenase-catalyzed hydroxylations in non-photosynthetic cells

In this study, we coupled a well-established whole-cell system based on E. coli via light-harvesting complexes to Rieske oxygenase (RO)-catalyzed hydroxylations in vivo . Although these enzymes represent very promising biocatalysts, their practical applicability is hampered by their dependency on NAD(P)H as well as their multi-component nature and intrinsic instability in cell-free systems. In order to explore the boundaries of E. coli as chassis for artificial photosynthesis, and due to the reported instability of ROs, we used these challenging enzymes as model system. The light-driven approach relies on light-harvesting complexes such as eosin Y, 5(6)-carboxyeosin or rose bengal and sacrificial electron donors (EDTA, MOPS and MES) that were easily up-taken by the cells. The obtained product formations of up to 1.3 g/L and rates of up to 1.6 mM/h demonstrate that this is a comparable approach to typical whole-cell transformations in E. coli . The applicability of this photocatalytic synthesis has been demonstrated and represents the first example of a photo-induced RO system.