CO₂ upgrading into bioproducts using a two-step abiotic-biotic system.

Area of Science:

• Chemical Engineering
• Biotechnology
• Sustainable Chemistry

Background:

• Direct electrosynthesis of carbon molecules (C_n, n > 4) from CO₂ is challenging.
• Valorization of CO₂ to higher-value chemicals is of significant interest.

Purpose of the Study:

• To develop a two-step abiotic-biotic system for upgrading CO₂ into the biopolymer poly(3-hydroxybutyrate).
• To demonstrate the feasibility of this system for sustainable chemical manufacturing.

Main Methods:

• Utilized a Cu-Ag tandem electrocatalyst to convert CO₂ into C₂ oxygenates (acetate).
• Employed *Cupriavidus necator* in a bioreactor to upgrade electrosynthesized acetate into biopolymer.
• Demonstrated purification of the resulting biopolymer into powder.

Main Results:

• Electrolysis produced a bio-compatible liquid stream with ~200 mM acetate.
• Biopolymer production rate achieved was 32 ± 3.5 mg L^-1 h^-1.
• Successfully purified the biopolymer into a powder.

Conclusions:

• The developed abiotic-biotic system efficiently upgrades CO₂ to poly(3-hydroxybutyrate).
• The high productivity indicates feasibility for sustainable chemical manufacturing.
• This approach offers a promising route for CO₂ valorization beyond simple C_1-2 products.