From photon to product : development and quantitative assessment of photosynthesis-driven oxygenase biocatalysis with cyanobacteria

Abstract

Cyanobacteria are promising whole-cell biocatalysts for sustainable production light-driven processes. Heterologous oxygenases can profit from photosynthesis-derived reduction equivalents and O2 for biocatalysis. Here, a Cytochrome P450 monooxygenase and a Baeyer-Villiger monooxygenase were established, characterized, and optimized on the genetic and reaction level. With these model systems we investigated i) which electron routes can be used to couple heterologous redox reactions to photosynthesis, ii) how efficient electron transfer to heterologous redox reactions can be realized, and iii) at which rate photosynthetic electron supply can be tapped for production processes. The establishment of an in vivo enzyme cascade in a cyanobacterium marks another important progress, inter alia to overcome product inhibition. Combining biocatalyst and process engineering with a quantitative perspective on cyanobacteria is of significant interest for future developments in the field.