Synthesis of polylactic acid from solar C₂ chemicals in engineered Escherichia coli

Abstract

Current production of polylactic acid (PLA) relies on agricultural feedstocks. Utilizing solar chemicals produced from CO₂ by artificial photosynthesis offers a sustainable alternative for producing biodegradable plastics. However, the direct synthesis of PLA from CO₂ within a cell factory remains challenging. Here, we report the direct production of PLA in engineered Escherichia coli from CO₂ via ethanol or acetate, which are produced from CO₂ electrolysis with solar energy. More importantly, we found that cofeeding ethanol and acetate synergistically enhanced PLA production. The PLA titer under cofeeding condition reached 5-folds and 53-folds of those obtained with ethanol or acetate alone, respectively. This cofeeding effect upregulated the glyoxylate shunt, the Entner-Doudoroff pathway, and serine anabolism, which facilitated efficient lactic acid generation from acetyl-CoA. By further integrating electroreduction and PLA bioproduction, we achieved PLA synthesis from CO₂ with a titer of 241 mg/L. This work develops an agriculture-independent approach for bioplastic production from CO₂, H₂O, and renewable energy.

Graphical abstract

Keywords

Polylactic acid / Chemo-biological hybrid / C₂ conversion / Escherichia coli

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Funding

National Key Research and Development Program of China(2022YFC3401802)

National Natural Science Foundation of China(22088102)

RIGHTS & PERMISSIONS

Jiangnan University