Characterization of a thermostable flavin-containing monooxygenase from Nitrincola lacisaponensis (NiFMO)

  • Nikola Lončar
  • Filippo Fiorentini
  • Gautier Bailleul
  • Simone Savino
  • Elvira Romero
  • Andrea MatteviEmail author
  • Marco W. FraaijeEmail author
Biotechnologically relevant enzymes and proteins


The flavin-containing monooxygenases (FMOs) play an important role in drug metabolism but they also have a high potential in industrial biotransformations. Among the hitherto characterized FMOs, there was no thermostable representative, while such biocatalyst would be valuable for FMO-based applications. Through a targeted genome mining approach, we have identified a gene encoding for a putative FMO from Nitrincola lacisaponensis, an alkaliphilic extremophile bacterium. Herein, we report the biochemical and structural characterization of this newly discovered bacterial FMO (NiFMO). NiFMO can be expressed as active and soluble enzyme at high level in Escherichia coli (90–100 mg/L of culture). NiFMO is relatively thermostable (melting temperature (Tm) of 51 °C), displays high organic solvent tolerance, and accepts a broad range of substrates. The crystal structure of NiFMO was solved at 1.8 Å resolution, which allows future structure-based enzyme engineering. Altogether, NiFMO represents an interesting newly discovered enzyme with the appropriate features to develop into an industrially applied biocatalyst.


Monooxygenase Thermostability Indigo bioproduction 



We thank Callum R. Nicoll for his help in the project.

Funding information

Nikola Lončar was supported by the NWO-LIFT project Indigreen. Gautier Bailleul received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant Oxytrain, agreement No 722390. The financial support of the Fondazione Cariplo (grant 2015-0406) is acknowledged.

Compliance with ethical standards

This article does not contain any studies with human participants or animals performed by any of the authors.

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Groningen Enzyme and Cofactor Collection (GECCO)University of GroningenGroningenThe Netherlands
  2. 2.Molecular Enzymology GroupUniversity of GroningenGroningenThe Netherlands
  3. 3.Structural Biology Lab, Department of Biology and Biotechnology “L. Spallanzani”University of PaviaPaviaItaly

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