Identification and characterization of a hyperthermophilic GH9 cellulase from the Arctic Mid-Ocean Ridge vent field

Anton A Stepnov; Lasse Fredriksen; Ida H Steen; Runar Stokke; Vincent G H Eijsink

doi:10.1371/journal.pone.0222216

Identification and characterization of a hyperthermophilic GH9 cellulase from the Arctic Mid-Ocean Ridge vent field

PLoS One. 2019 Sep 6;14(9):e0222216. doi: 10.1371/journal.pone.0222216. eCollection 2019.

Authors

Anton A Stepnov¹, Lasse Fredriksen¹, Ida H Steen², Runar Stokke², Vincent G H Eijsink¹

Affiliations

¹ Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway.
² Department of Biological Sciences and KG Jebsen Centre for Deep Sea Research, University of Bergen, Bergen, Norway.

Abstract

A novel GH9 cellulase (AMOR_GH9A) was discovered by sequence-based mining of a unique metagenomic dataset collected at the Jan Mayen hydrothermal vent field. AMOR_GH9A comprises a signal peptide, a catalytic domain and a CBM3 cellulose-binding module. AMOR_GH9A is an exceptionally stable enzyme with a temperature optimum around 100°C and an apparent melting temperature of 105°C. The novel cellulase retains 64% of its activity after 4 hours of incubation at 95°C. The closest characterized homolog of AMOR_GH9A is TfCel9A, a processive endocellulase from the model thermophilic bacterium Thermobifida fusca (64.2% sequence identity). Direct comparison of AMOR_GH9A and TfCel9A revealed that AMOR_GH9A possesses higher activity on soluble and amorphous substrates (phosphoric acid swollen cellulose, konjac glucomannan) and has an ability to hydrolyse xylan that is lacking in TfCel9A.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Arctic Regions
Bacteria / metabolism*
Cellulase / metabolism*
Data Mining
Databases, Genetic
Hydrothermal Vents / microbiology*
Metagenome*
Oceans and Seas

Substances

Cellulase

Grants and funding

This work was funded by the Research Council of Norway through the NorZymeD project, project number 221568 (VGHE). Infrastructure was in part supported by NorBioLab grants 226247 and 270038 provided by the Research Council of Norway (VGHE). The research cruise to the Arctic Mid-Ocean Ridge vent fields was funded by the Research Council of Norway, project number 179560 (IHS).