High-throughput in-field bioprospecting for cyanogenic plants and hydroxynitrile lyases

Mihai-Silviu Tomescu, Deidre Davids, Matthew DuPlessis, Barbara Darnhofer, Ruth Birner-Gruenberger, Robert Archer, Daniel Schwendenwein, Gerhard Thallinger, Margit Winkler, Karl Rumbold

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Hydroxynitrile lyases (HNLs) are sought-after, stereo-selective biocatalysts used in the agrochemical, pharmaceutical and fine chemical industries to produce cyanohydrin enantiomers. There are several approaches for the discovery of HNLs, most of which are methodologically demanding and not suitable for high-throughput. Bioprospecting studies to date have also been constrained/limited to commercialised plants or botanical gardens, leaving a vast majority of plant species untested for HNL activity or cyanogenesis. To increase the rate of discovery of HCN liberating plants, we devised a Feigl-Anger microfuge tube that is portable and capable of high throughput detection of naturally cyanogenic plants. A workflow suitable for detecting plant candidates containing extractable, novel HNLs was subsequently applied. In this study, we screened over 600 plants for cyanogenic activity as well as the ability to degrade racemic mandelonitrile. We detected 33 plants able to degrade racemic mandelonitrile, of which, 25 were identified to the species level. Six of these plants were found to be naturally cyanogenic. Protein extracts from 5 of the naturally cyanogenic plants retained the ability to degrade racemic mandelonitrile pointing to five yet undescribed enzymes in the species Achyranthes aspera, Davallia trichomonoides, Morus mesozygia, Polypodium aureum “Mandaianum”, and Thelypteris confluens. In contrast, although Acalypha glabrata was found to be naturally cyanogenic, the protein extract did not break down racemic mandelonitrile. Here, we used racemic mandelonitrile as substrate and detected enzymes with mandelonitrile lyase activity, however, any cyanohydrin could be used as part of the approach taken here to detect novel HNLs specific to the substrate utilised
Original languageEnglish
Pages (from-to)234-240
JournalBiocatalysis and Biotransformation
Issue number3
Publication statusPublished - 2020


Fields of Expertise

  • Human- & Biotechnology

Cite this

Tomescu, M-S., Davids, D., DuPlessis, M., Darnhofer, B., Birner-Gruenberger, R., Archer, R., ... Rumbold, K. (2020). High-throughput in-field bioprospecting for cyanogenic plants and hydroxynitrile lyases. Biocatalysis and Biotransformation, 38(3), 234-240. https://doi.org/10.1080/10242422.2020.1726895