Upcycling surplus acetone into long-chain chemicals using a tandem electro-biosystem

The chemical industry faces the pressing issue of managing excess by-products: for example, the phenol sector produces acetone as a by-product in vast quantities exceeding the market demand for acetone. Integrating electrocatalysis and bioengineering offers versatile access to repurposing these by-products into a wide range of valuable commodities. Nevertheless, the lack of suitable intermediate feedstocks prevents smooth integration of the hybrid electro-biosystem. Here we introduce a tandem electro-biosystem that effectively transforms excess acetone from the phenol industry into valuable long-chain compounds using pure isopropyl alcohol (IPA) as an intermediate feedstock. We developed an intercalated ruthenium electrocatalyst that achieves a maximal Faradaic efficiency of 95.6% for acetone-to-IPA conversion, with an IPA partial current density of −240 mA cm−2. We also showed the complete conversion of acetone to ~100% pure IPA using a bipolar membrane electrode assembly device and intercalated ruthenium. We then metabolically engineered the yeast Saccharomyces cerevisiae, which can directly feed on electrogenerated pure IPA as a carbon source, secreting p-coumaric acid, free fatty acids or lycopene. This work underscores advancements in the repurposing of industrial by-products and highlights opportunities to reshape the traditional chemical industry using electricity.