In vivo Olefin Metathesis in Microalgae Upgrades Lipids to Building Blocks for Polymers and Chemicals

Abstract

Sustainable sources are key to future chemicals production. Microalgae are promising renewable resources as they fixate atmospheric carbon dioxide to organic molecules by photosynthesis, with sunlight as energy. Thereby they produce unsaturated fatty acids as established raw materials for the industrial production of chemical building blocks. Although these renewable feedstocks are generated inside cells, their synthetic catalytic upgrading to useful products requires ex vivo transformations. A synthetic catalysis inside living photoautotrophic cells has remained elusive. Here we show that a catalytic conversion of renewable substrates can be realized directly inside living microalgae. Organometallic catalysts are internalized and remain active inside the photoautotrophic cells, enabling in vivo catalytic olefin metathesis as new-to-nature transformation. Stored lipids are converted in vivo to alkenes and long-chain dicarboxylates as valuable building blocks for polymers. This is a key step towards the long-term goal of producing desired renewable chemicals in microalgae as living "cellular factories".