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General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.
• Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Downloaded from orbit.dtu.dk on: Jul 07, 2018
Enzymatic isomerization of glucose and xylose in ionic liquids
Ståhlberg, Tim Johannes Bjarki; Woodley, John; Riisager, Anders
Published in:Catalysis Science & Technology
Link to article, DOI:10.1039/c1cy00155h
Publication date:2012
Document VersionPublisher's PDF, also known as Version of record
Link back to DTU Orbit
Citation (APA):Ståhlberg, T. J. B., Woodley, J., & Riisager, A. (2012). Enzymatic isomerization of glucose and xylose in ionicliquids. Catalysis Science & Technology, 2(2), 291-295. DOI: 10.1039/c1cy00155h
recovery of the sugars after reaction was achieved by extraction
with aqueous HCl, thus making the protocol attractive for
continuous operation.
Introduction
The increased demand for sustainable and environmentally
benign chemical processes makes enzymes attractive alterna-
tives as catalysts in industrial processes. Enzymes are by virtue
most effective in aqueous environments where many chemical
substrates and products have low solubility. Therefore the
search for alternative solvents in which enzymes have retained
activity is of the essence.
Ionic liquids (ILs) are interesting alternatives to conventional
organic solvents due to their negligible vapor pressure, non-
flammability and unique dissolving abilities for polar compounds
and polymers.1 The study of enzymes in ILs has intensified over
recent years and many interesting examples are covered in two
excellent reviews by Sheldon and coworkers.2,3 In particular lipases
have proven to be stable and have retained or improved activity in
ILs.4–15Other noteworthy examples are the synthesis of aspartame
with thermolysin in 1-butyl-3-methylimidazolium hexafluoro-
phosphate ([BMIm][PF6])16 and the oxidation of cellobiose
with cytochrome c in hydrated choline dihydrogen phosphate
([Choline][dhp]).17,18 An additional advantage with ILs in
combination with enzymes is the possibility for two-phase systems
with supercritical fluids. Combining IL/enzyme mixtures with
supercritical CO2 enables a dynamic system where products or
reactants can be selectively removed from the reaction mixture.4
Glucose isomerase (GI) catalyzes the isomerization of
glucose to fructose and is used for the production of high-
fructose corn syrup (HFCS) which is currently one of the most
important industrial bioprocesses (Scheme 1).19 The process is
limited by the poor yield of fructose and in spite of significant
research on enriching fructose, the process currently requires an
expensive chromatographic step to achieve the desired fructose
concentration.19–21 The process usually works in water and
examples in the literature of GI in alternative solvents are
scarce, nevertheless successful isomerization has been achieved
in aqueous ethanol, indicating that GI can maintain activity at
reduced water concentrations.22 Finding an IL system where GI
could exhibit activity would be of significant interest, not only
for the food industry, but also since it potentially make one-pot
reactions for future platform chemicals such as 5-hydroxy-
methyl furfural (HMF) possible. HMF is formed via the
dehydration of hexoses and is readily obtained from fructose
while the conversion from glucose requires special catalysts.23
HMF and its derivatives are believed to be among the most
important platform chemicals of the future biopetrochemical
industry.24 Given the high solubility of carbohydrates in ILs25
and the irreversible hydrolysis of HMF in aqueous solutions
Scheme 1 Isomerization of glucose to fructose and its further
derivatization to biopetrochemicals.
a Centre for Catalysis and Sustainable Chemistry, Department ofChemistry, Technical University of Denmark, DK-2800 Kgs. Lyngby,Denmark. E-mail: [email protected]
bCentre for Process Engineering and Technology, Department ofChemical and Biochemical Engineering, Technical University ofDenmark, DK-2800 Kgs. Lyngby, Denmark
w Electronic supplementary information (ESI) available. See DOI:10.1039/c1cy00155h
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water (0–0.2 mL) and sugar (100 mg, 9 wt%) were stirred for
5 minutes and a clear homogeneous solution was obtained.
Sweetzymes (30 mg) was added and the reaction was allowed
to stir for a maximum of 72 hours. Samples were taken out
during the reaction and analyzed by HPLC.
Conclusions
The first successful enzymatic conversion of glucose to fructose as
well as xylose to xylulose in ILs is reported. During isomerization
of glucose the formed fructose was converted to mannose via
the Lobry-de Bruyn–van Ekenstein transformation leading to
an accumulation of fructose and mannose at the expense of
glucose over time. The activity of the enzyme was lower in ILs
in comparison to water resulting in slower reaction rates.
Xylose isomerization was, however, faster in comparison to
glucose as would be expected being the natural substrate of the
enzyme. It is reasonable to believe that the surface of
the enzyme is hydrated and hence facilitates activity even in
the presence of the IL. Analogous to the previous report on
ethanol22 21 wt% of water was used for the reactions. In this
study, however, solubility of the sugar and MgSO4—not
enzyme activity—was the main reason for using this particular
solvent composition.
The conversion of biomass to commodity chemicals is
alongside the production of sweeteners the most important
future application of this catalytic system. Hence, our work
will continue with studies of fructose dehydration to HMF
using Lewis and Brønsted acid catalysts like, e.g. WCl6,33
CrCl3,34,35 or HCl36 in DBAO at elevated temperatures.
We believe that this work provides interesting discoveries
concerning the compatibility of GI and ILs and could initiate
further studies on GI in alternative solvents. Furthermore, it
facilitates opportunities to make a one-pot synthesis of platform
chemicals from glucose or its natural polymers.
Acknowledgements
The reported work was supported by the Danish National
Advanced Technology Foundation in cooperation with
Novozymes A/S. Special gratitude to BASF for providing
the ionic liquids.
Notes and references
1 P. Wasserscheid and T. Welton, Ionic Liquids in Synthesis,Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
2 R. A. Sheldon, R. M. Lau, M. J. Sorgedrager, F. van Rantwijk andK. R. Seddon, Green Chem., 2002, 4, 147–151.
3 F. van Rantwijk and R. A. Sheldon, Chem. Rev., 2007, 107,2757–2785.
4 R. Bogel-Łukasik, V. Najdanovic-Visak, S. Barreiros andM. Nunes da Ponte, Ind. Eng. Chem. Res., 2008, 47, 4473–4480.
5 R. M. Lau, F. van Rantwijk, K. R. Seddon and R. A. Sheldon,Org. Lett., 2000, 2, 4189–4191.
6 M. Eckstein, P. Wasserscheid and U. Kragl, Biotechnol. Lett.,2002, 24, 763–767.
7 P. Lozano, T. de Diego, D. Carrie, M. Vaultier and J. L. Iborra,Chem. Commun., 2002, 692–693.
8 M. T. Reetz, W. Wiesenhofer, G. Francio and W. Leitner, Chem.Commun., 2002, 992–993.
9 R. M. Lau, M. J. Sorgedrager, G. Carrea, F. van Rantwijk,F. Secundo and R. A. Sheldon, Green Chem., 2004, 6, 483–487.
10 T. De Diego, P. Lozano, S. Gmouh, M. Vaultier and J. L. Iborra,Biomacromolecules, 2005, 6, 1457–1464.
11 F. van Rantwijk, F. Secundo and R. A. Sheldon, Green Chem.,2006, 8, 282–286.
12 H. Shan, Z. Li, M. Li, G. Ren and Y. Fang, J. Chem. Technol.Biotechnol., 2008, 83, 886–891.
13 R. Bogel-Łukasik, N. M. T. Lourenco, P. Vidinha, M. D. R.Gomes da Silva, C. A. M. Afonso, M. Nunes da Ponte andS. Barreiros, Green Chem., 2008, 10, 243–248.
14 Z. Guo and X. Xu, Org. Biomol. Chem., 2005, 3, 2615–2619.15 M. Adamczak and U. T. Bornscheuer, Process Biochem., 2009, 44,
257–261.16 M. Erbeldinger, A. J. Mesiano and A. J. Russell, Biotechnol. Prog.,
2000, 16, 1129–1131.17 K. Fujita, D. R. MacFarlane, M. Forsyth, M. Yoshizawa-Fujita,
K. Murata, N. Nakamura and H. Ohno, Biomacromolecules, 2007,8, 2080–2086.
18 K. Fujita, N. Nakamura, K. Igarashi, M. Samejima and H. Ohno,Green Chem., 2009, 11, 351–354.
Fig. 5 Enzymatic conversion of xylose to xylulose in DBAO at 60 1C.
Reaction conditions: 100 mg xylose, 0.8 g DBAO, 0.2 mL H2O, 30 mg