title: Pushing the equilibrium of regio-complementary carboxylation of phenols and hydroxystyrene derivatives.
abstract: The enzymatic carboxylation of electron-rich aromatics, which represents a promising 'green' equivalent to the chemical Kolbe-Schmitt reaction, is thermodynamically disfavored and is therefore impeded by incomplete conversions. Optimization of the reaction conditions, such as pH, temperature, substrate concentration and the use of organic co-solvents and/or ionic liquids allowed to push the conversion in favor of carboxylation by a factor of up to 50%. Careful selection of the type of bicarbonate salt used as CO2 source was crucial to ensure optimal activities. Among two types of carboxylases tested with their natural substrates, benzoic acid decarboxylase from Rhizobium sp. proved to be significantly more stable than phenolic acid decarboxylase from Mycobacterium colombiense; it tolerated reaction temperatures of up to 50 °C and substrate concentrations of up to 100mM and allowed efficient biocatalyst recycling.
authors.affiliation: ACIB GmbH, Petersgasse 14, 8010 Graz, Austria; Department of Chemistry, Organic & Bioorganic Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria.
authors.forename: Christiane
authors.initials: C
authors.lastname: Wuensch
authors.forename: Nina
authors.initials: N
authors.lastname: Schmidt
authors.forename: Johannes
authors.initials: J
authors.lastname: Gross
authors.forename: Barbara
authors.initials: B
authors.lastname: Grischek
authors.forename: Silvia M
authors.initials: SM
authors.lastname: Glueck
authors.forename: Kurt
authors.initials: K
authors.lastname: Faber
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001639:Bicarbonates / Q000378:metabolism; D055162:Biocatalysis; D002262:Carboxy-Lyases / Q000378:metabolism*; D002617:Chemical Industry; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D009161:Mycobacterium / Q000201:enzymology*; D010636:Phenols / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012231:Rhizobium / Q000201:enzymology*; D012997:Solvents; D013343:Styrenes / Q000737:chemistry* / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D001639:Bicarbonates; D010636:Phenols; D011994:Recombinant Proteins; D012997:Solvents; D013343:Styrenes; C488807:2,6-dihydroxybenzoate decarboxylase; D002262:Carboxy-Lyases; C417714:phenolic acid decarboxylase
keywords: 1,3-dimethylimidazolium; 1-butyl-3-methylimidazolium; 1-ethyl-3-methylimidazolium; 2,6-DHBA; 2,6-DHBD_Rs; 2,6-dihydroxybenzoic acid; 2,6-dihydroxybenzoic acid decarboxylase from Rhizobium sp.; BMIM; Biotransformation; Carboxylation; DHBD; DMIM; Decarboxylase; EMIM; Kolbe–Schmitt reaction; PAD; PAD_Mc; PEG; benzoic acid decarboxylase; phenolic acid decarboxylase; phenolic acid decarboxylase from Mycobacterium colombiense; polyethylene glycol