Hybrid synthesis of polyhydroxybutyrate bioplastics from carbon dioxide

Abstract

Global sustainable development has intensified the demand for switching to a renewable economy with a reduced carbon footprint. Here, we report a hybrid system, coupling a chemical process for CO₂ reduction with hydrogen, and a biological process for polyhydroxybutyrate (PHB) synthesis, capable of converting CO₂ into bioplastics with a theoretical carbon yield of 100%. The synthetic pathway from CO₂ to PHB was modularly optimized by improving the catalytic efficiency of key enzymes, avoiding the kinetic trap of metabolic flux and optimizing the whole catalytic process, resulting in 5.96 g L⁻¹ PHB with a productivity of 1.19 g L⁻¹ h⁻¹ and a molar CO₂ utilization efficiency of 71.8%. These results represent a promising closed-loop production process from CO₂ to biodegradable plastics.