Isothermal titration calorimetric assessment of lignin conversion by laccases

Journal Article (2021)
Author(s)

Shams T. Shams (External organisation)

Jie Zhang (Chongqing Technology and Business University)

Fabio Tonin (TU Delft - BT/Biocatalysis)

Renske Hinderks (Student TU Delft)

Y.N. Deurloo (TU Delft - BN/Dimphna Meijer Lab)

Vlada B. Urlacher (Universität Düsseldorf)

PL Hagedoorn (TU Delft - BT/Biocatalysis)

Research Group
BT/Biocatalysis
Copyright
© 2021 Shams T. Shams, Jie Zhang, F. Tonin, Renske Hinderks, Y.N. Deurloo, Vlada B. Urlacher, P.L. Hagedoorn
DOI related publication
https://doi.org/10.1002/bit.27991
More Info
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Publication Year
2021
Language
English
Copyright
© 2021 Shams T. Shams, Jie Zhang, F. Tonin, Renske Hinderks, Y.N. Deurloo, Vlada B. Urlacher, P.L. Hagedoorn
Research Group
BT/Biocatalysis
Issue number
2
Volume number
119
Pages (from-to)
493-503
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Abstract

Lignin valorization may offer a sustainable approach to achieve a chemical industry that is not completely dependent on fossil resources for the production of aromatics. However, lignin is a recalcitrant, heterogeneous, and complex polymeric compound for which only very few catalysts can act in a predictable and reproducible manner. Laccase is one of those catalysts and has often been referred to as an ideal “green” catalyst, as it is able to oxidize various linkages within lignin to release aromatic products, with the use of molecular oxygen and formation of water as the only side product. The extent and rate of laccase-catalyzed lignin conversion were measured using the label-free analytical technique isothermal titration calorimetry (ITC). IITC provides the molar enthalpy of the reaction, which reflects the extent of conversion and the time-dependent power trace, which reflects the rate of the reaction. Calorimetric assessment of the lignin conversion brought about by various fungal and bacterial laccases in the absence of mediators showed marked differences in the extent and rate of conversion for the different enzymes. Kraft lignin conversion by Trametes versicolor laccase followed Michaelis–Menten kinetics and was characterized by the following thermodynamic and kinetic parameters ΔHITC = −(2.06 ± 0.06)·103 kJ mol−1, KM = 6.6 ± 1.2 μM and Vmax = 0.30 ± 0.02 U/mg at 25°C and pH 6.5. We envision calorimetric techniques as important tools for the development of enzymatic lignin valorization strategies.