Antarctic rahnella inusitata: A producer of cold-stable β-galactosidase enzymes

Kattia Núñez-Montero, Rodrigo Salazar, Andrés Santos, Olman Gómez-Espinoza, Scandar Farah, Claudia Troncoso, Catalina Hoffmann, Damaris Melivilu, Felipe Ignacio Scott, Leticia Barrientos Díaz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


There has been a recent increase in the exploration of cold-active β-galactosidases, as it offers new alternatives for the dairy industry, mainly in response to the current needs of lactose-intolerant consumers. Since extremophilic microbial compounds might have unique physical and chemical properties, this research aimed to study the capacity of Antarctic bacterial strains to pro-duce cold-active β-galactosidases. A screening revealed 81 out of 304 strains with β-galactosidase activity. The strain Se8.10.12 showed the highest enzymatic activity. Morphological, biochemical, and molecular characterization based on whole-genome sequencing confirmed it as the first Rahnella inusitata isolate from the Antarctic, which retained 41–62% of its β-galactosidase activity in the cold (4 C–15 C). Three β-galactosidases genes were found in the R. inusitata genome, which belong to the glycoside hydrolase families GH2 (LacZ and EbgA) and GH42 (BglY). Based on molecular docking, some of these enzymes exhibited higher lactose predicted affinity than the commercial control enzyme from Aspergillus oryzae. Hence, this work reports a new Rahnella inusitata strain from the Antarctic continent as a prominent cold-active β-galactosidase producer.

Original languageEnglish
Article number4144
JournalInternational Journal of Molecular Sciences
Issue number8
StatePublished - 16 Apr 2021

Bibliographical note

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© 2021 by the authors. Licensee MDPI, Basel, Switzerland.


  • Antarctica
  • Cold-adapted bacteria
  • Extremozymes
  • Galactosidase
  • Lactose


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