Optimized oxidoreductases for medium and large scale industrial biotransformations
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Dr Marta Pérez-Boada
E-mail: MPBoada@cib.csic.es
Consejo Superior de Investigaciones Científicas (CSIC)
Biological Research Centre (CIB)
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publications
Total records: 126
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[ 2015 ] Poraj-Kobielska M, Peter S, Leonhardt S, Ullrich R, Scheibner K, Hofrichter M Immobilization of unspecific peroxygenases (EC 1.11.2.1) in PVA/PEG gel and hollow fiber modules Biochem. Eng. J., 98: 144-150
[ 2015 ] Rico A, Rencoret J, del Río JC, Martínez AT, Gutiérrez A In-Depth 2D NMR Study of Lignin Modification During Pretreatment of Eucalyptus Wood with Laccase and Mediators Bioenerg. Res., 8: 211-230
[ 2015 ] Saez-Jimenez V, Acebes S, Guallar V, Martínez AT, Ruiz-Dueñas FJ Improving the oxidative stability of a high redox potential fungal peroxidase by rational design PlosOne, 10-4
[ 2015 ] Saez-Jimenez V, Baratto MC, Pogni R, Rencoret J, Gutiérrez A, Santos JI, Martínez AT, Ruiz-Dueñas FJ Demonstration of Lignin-to-Peroxidase Direct Electron Transfer: A Transient-state Kinetics, Directed Mutagenesis, EPR and NMR Study J. Biol. Chem., 290: 23201-23213
[ 2015 ] Saez-Jimenez V, Fernandez-Fueyo E, Medrano FJ, Romero A, Martínez AT, Ruiz-Dueñas FJ Improving the pH-stability of Versatile Peroxidase by Comparative Structural Analysis with a Naturally-Stable Manganese Peroxidase PlosOne, doi: 10.1371/journal.pone.0140984
[ 2015 ] Tan TC, Kracher D, Gandini R, Sygmund C, Kittl R, Haltrich D, Hällberg BM, Ludwig R, Divine C Structural basis for cellobiose dehydrogenase action during oxidative cellulose degradation Nat. Commun., 6: 7542
year2014
Engineering a fungal peroxidase that degrades lignin at very acidic pH
Fernandez-Fueyo E, Ruiz-Dueñas FJ, Martínez AT
Biotechnol. Biofuels, 7: 114

Background
Ligninolytic peroxidases are divided into three families: manganese peroxidases (MnPs), lignin peroxidases (LiPs), and versatile peroxidases (VPs). The latter two are able to degrade intact lignins, as shown using nonphenolic lignin model compounds, with VP oxidizing the widest range of recalcitrant substrates. One of the main limiting issues for the use of these two enzymes in lignocellulose biorefineries (for delignification and production of cellulose-based products or modification of industrial lignins to added-value products) is their progressive inactivation under acidic pH conditions, where they exhibit the highest oxidative activities.

Results
In the screening of peroxidases from basidiomycete genomes, one MnP from Ceriporiopsis subvermispora was found to have a remarkable acidic stability. The crystal structure of this enzyme recently became available and, after comparison with Pleurotus ostreatus VP and Phanerochaete chrysosporium LiP structures, it was used as a robust scaffold to engineer a stable VP by introducing an exposed catalytic tryptophan, with different protein environments. The variants obtained largely maintain the acidic stability and strong Mn2+-oxidizing activity of the parent enzyme, and the ability to oxidize veratryl alcohol and Reactive Black 5 (two simple VP substrates) was introduced. The engineered peroxidases present more acidic optimal pH than the best VP from P. ostreatus, enabling higher catalytic efficiency oxidizing lignins, by lowering the reaction pH, as shown using a nonphenolic model dimer.

Conclusions
A peroxidase that degrades lignin at very acidic pH could be obtained by engineering an exposed catalytic site, able to oxidize the bulky and recalcitrant lignin polymers, in a different peroxidase type selected because of its high stability at acidic pH. The potential of this type of engineered peroxidases as industrial biocatalysts in lignocellulose biorefineries is strongly enhanced by the possibility to perform the delignification (or lignin modification) reactions under extremely acidic pH conditions (below pH 2), resulting in enhanced oxidative power of the enzymes.

Official webpage of indox [ industrialoxidoreductases ]. Optimized oxidoreductases for medium and large scale industrial biotransformations. This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under Grant Agreement nº: FP7-KBBE-2013-7-613549. © indox 2013. Developed by garcíarincón