Reversible enzymatic decarboxylation reactions are known for their thermodynamic limitations regarding the carboxylation. Significant thermodynamic and kinetic improvements were achieved for the carboxylation of resorcinol by the 2,6-dihydroxybenzoic acid decarboxylase from Rhizobium sp. utilizing the amine scrubber triethanolamine for CO₂ mediation. In a first approach, maximal yields of up to 50 % are achieved and are found to correlate with the CO₂ loading capacity of triethanolamine. In a second approach, application of quaternary amines for in situ carboxylation product removal by precipitation improves the achievable yields depending on utilized amine concentration. This demonstrates the possibility for a reusable system. By variation of hydrated CO₂ species ratio and concentration, CO₂ and alternatively H₂CO₃ is identified acting as second substrate.
