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Amine‐Mediated Enzymatic Carboxylation of Phenols Using CO 2 as Substrate Increases Equilibrium Conversions and Reaction Rates
Author(s) -
Pesci Lorenzo,
Gurikov Pavel,
Liese Andreas,
Kara Selin
Publication year - 2017
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201700332
Subject(s) - carboxylation , chemistry , substrate (aquarium) , bicarbonate , amine gas treating , enzyme , organic chemistry , kinetics , aspergillus oryzae , cofactor , combinatorial chemistry , stereochemistry , catalysis , oceanography , geology , physics , quantum mechanics
A variety of strategies is applied to alleviate thermodynamic and kinetic limitations in biocatalytic carboxylation of metabolites in vivo. A key feature to consider in enzymatic carboxylations is the nature of the cosubstrate: CO 2 or its hydrated form, bicarbonate. The substrate binding and activation mechanism determine what the actual carboxylation agent is. Dihydroxybenzoic acid (de)carboxylases catalyze the reversible regio‐selective ortho ‐(de)carboxylation of phenolics. These enzymes have attracted considerable attention in the last 10 years due to their potential in substituting harsh conditions typical of chemical carboxylations (100–200 °C, 5–100 bar) with, ideally, greener ones (20–40 °C, 1 bar). They are reported to use bicarbonate as substrate, needed in large excess to overcome thermodynamic and kinetic limitations. Therefore, CO 2 can be used as substrate by these enzymes only if it is converted into bicarbonate in situ. In this contribution, we report the simultaneous amine‐mediated conversion of CO 2 into bicarbonate and the ortho ‐carboxylation of different phenolic molecules catalyzed by 2,3‐dihydroxybenzoic acid (de)carboxylase from Aspergillus oryzae . Our results show that under the newly developed conditions a significant thermodynamic (up to twofold increase in conversion) and kinetic improvement (up to approx. fivefold increase in rate) of the biocatalytic carboxylation of catechol is achieved.