(127e) Integrated Electro-Microbial Conversion of CO2 to Bioplastics

Climate change due to greenhouse emission and plastics contamination are two significant environmental challenges for 21^st century. A sustainable platform to convert CO2 to plastics is highly desirable as it presents a potential carbon neutral route to mitigate CO2 emission and plastics contamination. However, integrating catalytic CO2 reduction with bioconversion have been limited by inefficient electron and mass transfers, unfavorable metabolic kinetics, and inadequate molecular building blocks. We have overcome those challenges by designing a novel chemical-biological interface to integrate electrocatalysis and microbial fermentation. The soluble C2 intermediates produced from CO2 electrochemical reduction facilitate rapid mass transfer, present as favorable microbial substrates and less toxicity, and serve as an ideal molecular building blocks for longer carbon chain commodity chemicals. In this work, we present a multi-tier chem-bio interface design that has achieved six and eight times increase of microbial biomass productivity compared to the previous C1 intermediate and hydrogen-driven routes, respectively. The product, medium-chain-length polyhydroxyalkanoates (PHAs), as biodegradable polymers, presents a sustainable pathway to electrify the carbon tensive polymer industry and decarbonize the non-degradable plastics.