Share:

Green Chem., 2018, 20,1754-1759
DOI: 10.1039/C8GC00008E, Communication

Open Access

  This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.

Katharina Plasch, Gerhard Hofer, Walter Keller, Sam Hay, Derren J. Heyes, Alexander Dennig, Silvia M. Glueck, Kurt Faber
Utilization of gaseous carbon dioxide as a C₁-building block in the biocatalytic ortho-carboxylation of a phenol.
The content of this RSS Feed (c) The Royal Society of Chemistry

http://pubs.rsc.org/en/content/articlehtml/2018/gc/c8gc00008e

Pressurized CO2 as a carboxylating agent for the biocatalytic ortho-carboxylation of resorcinol

Pressurized CO₂ as a carboxylating agent for the biocatalytic ortho-carboxylation of resorcinol

Katharina Plasch,^a  Gerhard Hofer,^b  Walter Keller,^b  Sam Hay,^c  Derren J. Heyes,^c  Alexander Dennig,^d  Silvia M. Glueck*^ae  and  Kurt Faber*^a 

Author affiliations

* Corresponding authors

^a Department of Chemistry, Organic & Bioorganic Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
E-mail:Si.Glueck@Uni-Graz.at, Kurt.Faber@Uni-Graz.at

^b Institute of Molecular Biosciences, University of Graz, Humboldstrasse 50, 8010 Graz, Austria

^c Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK

^d Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Petersgasse 12, 8010 Graz, Austria

^e Austrian Centre of Industrial Biotechnology (ACIB), Petersgasse 14, 8010 Graz, Austria

Abstract

The utilization of gaseous carbon dioxide instead of bicarbonate would greatly facilitate process development for enzyme catalyzed carboxylations on a large scale. As a proof-of-concept, 1,3-dihydroxybenzene (resorcinol) was carboxylated in the ortho-position using pressurized CO₂ (∼30–40 bar) catalyzed by ortho-benzoic acid decarboxylases with up to 68% conversion. Optimization studies revealed tight pH-control and enzyme stability as the most important determinants.

Fig. 1 (a) Enzyme-catalyzed de/carboxylation of resorcinol (1). Carboxylated product 2 is a mixture of regio-isomeric 2,6- (2,6-dhba, 2a) and 2,4-dihydroxybenzoic acid (2,4-dhba, 2b) with a ratio of 3:4;10b (b) CO2 pressure dependence of the carboxylation of 1 using 2,3-DHBD_Ao; (c) carboxylation activity of decarboxylases with CO2 (30 bar) using 1 as a substrate; (d) stopped-flow measurements of the decarboxylation of 2,6-dhba (2a) with pressure-pretreated (≤1.5 kbar) 2,3-DHBD_Ao and 2,6-DHBD_Rs.

Conclusion

In summary, we have demonstrated that pressurized carbon dioxide can be used directly as a carboxylating agent in the enzyme catalyzed o-carboxylation of a phenol as an alternative to the high concentration of bicarbonate. Two enzyme candidates (2,3-DHBD_Ao and SAD_Tm) readily accepted the alternative CO₂ source for the carboxylation of the model substrate resorcinol. In contrast, 2,6-DHBD_Rs was inapplicable under CO₂ pressure due to irreversible inactivation, which was correlated to a decrease in pH caused by the dissociation of H₂CO₃.

Overall, the use of pressurized CO₂ gas significantly improves the efficiency of biocatalytic carboxylations and facilitates downstream-processing of this benign and sustainable approach in using CO₂ as a carbon feedstock for the synthesis of organic acids.

DOCTORAL STUDENT,

Katharina Plasch

tel: +43-316-380-8646
e-mail:katharina.plasch(at)uni-graz.at

Katharina Plasch

Kurt Faber
Institute of Chemistry – Organic & Bioorganic Chemistry
Karl Franzens Universität Graz
Heinrichstrasse 28
8010 Graz

e-Mail: kurt.faber@uni-graz.at
phone: +43 316 380 5332
fax: +43 316 380 9840
web: http://biocatalysis.uni-graz.at

Kurt Faber, born 1953 in Klagenfurt (Carinthia/Austria), studied chemistry at the University of Graz, where he received his PhD in 1982. After a post-doctoral fellowship from 1982 to 1983 in St. John’s (Canada) he continued his career at the University of Technology in Graz, where he became associate professor in 1997. The following year he was appointed full professor at the University of Graz, where he since heads a research group devoted to the use of biocatalysts for the transformation of non-natural compounds. He was a visiting scientist at University of Tokyo (1987/1988), Exeter University (1990), University of Trondheim (1994), Stockholm University (2001) and University of Minnesota (2005).

Silvia M. Glueck

Silvia M. Glueck, born 1973 in Bruck/Mur (Austria), studied Chemistry at the University of Graz, where she received her PhD under the supervision of Prof. K. Faber in 2004. From 2005 to 2006 she worked as a post-doctoral fellow with Prof. N. J. Turner at the University of Edinburgh and the University of Manchester (MIB). In 2007 she returned to the University of Graz to join Prof. W. Kroutil, and in 2008 she became Research Scientist at the Research Centre Applied Biocatalysis in the group of Prof. K. Faber. Her research interests are focusing on biocatalysis, molecular biology and organic synthesis.

Tweet