Engineering towards catalytic use of fungal class-II peroxidases for dye-decolorizing and conversion of lignin model compounds

Taina Lundell, Elodie Bentley, Kristiina Hildén, Johanna Rytioja, Jaana Kuuskeri, Usenobong F. Ufot, Paula Nousiainen, Martin Hofrichter, Matti Wahlsten, Wendy Doyle, Andrew T. Smith

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Background: Manganese peroxidases (MnP) and lignin peroxidases (LiP) are haem-including fungal secreted class-II peroxidases, which are interesting oxidoreductases in protein engineering aimed at designing of biocatalysts for lignin and lignocellulose conversion, dye compound degradation, activation of aromatic compounds, and biofuel production.

Objective. Recombinant short-type MnP (Pr-MnP3) of the white rot fungus Phlebia radiata, and its manganese- binding site (E40, E44, D186) directed variants were produced and characterized. To allow catalytic applications, enzymatic bleaching of Reactive Blue 5 and conversion of lignin-like compounds by engineered class- II peroxidases were explored.

Method: Pr-MnP3 and its variants were expressed in Escherichia coli. The resultant body proteins were lysed, purified and refolded into haem-including enzymes in 6-7% protein recovery, and examined spectroscopically and kinetically.

Results: Successful production of active enzymes was attained, with spectral characteristics of high-spin class-II peroxidases. Recombinant Pr-MnP3 demonstrated high affinity to Mn2+, which was noticeably affected by single (D186H/N) and double (E40H+E44H) mutations. Without addition of Mn2+, Pr- MnP3 was able to oxidize ABTS and decolorize Reactive Blue 5. Pc-LiPH8, its Trp-radical site variants, and engineered CiP-LiP demonstrated conversion of veratryl alcohol and dimeric non-phenolic lignin-model compounds (arylglycerol-β-aryl ethers) with production of veratraldehyde, which is evidence for cation radical formation with subsequent Cα-Cβ cleavage. Pc-LiPH8 and CiP variants were able to effectively oxidize and convert the phenolic dimer (guaiacylglycerol-β-guaiacyl ether).

Conclusion: Our results demonstrate suitability of engineered MnP and LiP peroxidases for dyedecolorizing, and efficiency of LiP and its variants for activation and degradation of phenolic and nonphenolic lignin-like aryl ether-linked compounds.
Original languageEnglish
Pages (from-to)116-127
Number of pages12
JournalCurrent Biotechnology
Volume6
Issue number2
DOIs
Publication statusPublished - 2017
MoE publication typeA1 Journal article-refereed

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