Towards an enzyme cascade synthesis of the bulk chemical acrylic acid.

Zhao, Haodong; Wang, Chunying; Zhang, Shiqing; Wang, Qian; Chu, Huanyu; Yang, Jinying; Zhang, Lei; Xu, Zhanmei et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Acrylic acid is a bulk chemical predominantly produced via fossil-based processes. Here, we repurpose and engineer a thiamine diphosphate (ThDP)-dependent enzyme to catalyze direct <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><msubsup><mrow><mi>PO</mi></mrow><mrow><mn>4</mn></mrow><mrow><mo>-</mo></mrow></msubsup></math> elimination from dihydroxyacetone phosphate (DHAP) for acrylic acid synthesis. Quantum chemical calculations reveal the catalytic mechanism involving isomerization, enol-ThDP intermediate formation, <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><msubsup><mrow><mi>PO</mi></mrow><mrow><mn>4</mn></mrow><mrow><mo>-</mo></mrow></msubsup></math> elimination, and hydrolysis. Using an automated high-throughput screening platform, we perform directed evolution and obtain a 13.6-fold improved variant, designated acrylic acid synthase (AAS). We establish an enzymatic methanol-to-acrylic acid (MAAP) pathway, achieving a titer of 4.3 g L<sup>-1</sup>, a productivity of 268.9 mg L<sup>-1</sup> h<sup>-1</sup>, and 99.5% conversion. This work establishes a high-efficiency biomanufacturing paradigm for bulk acrylic acid, and expands the catalytic repertoire of ThDP-dependent enzymes for sustainable one-carbon conversion.