biostudies-literatureTorosian NNASANational Aeronautics and Space AdministrationU.S. Department of Energy & Office of ScienceNational Science Foundation & Directorate for Biological SciencesNational Science Foundation1629-1642https://www.ebi.ac.uk/biostudies/studies/S-EPMC12485897biostudies-literatureUnknown15(10)Fervidibacter sacchari is an aerobic hyperthermophile belonging to the phylum Armatimonadota that degrades a variety of polysaccharides. Its genome encodes 117 enzymes with one or more annotated glycoside hydrolase (GH) domain, but the roles of these putative GHs in polysaccharide catabolism are poorly defined. Here, we describe one F. sacchari enzyme encoding a GH10 domain, Fsa02490Xyn, that was previously shown to be active on Miscanthus, oat β-glucan, and beech-wood xylan, with optimal activity at 90-100 °C. We show that Fsa02490Xyn is also active on birch-wood xylan and gellan gum. The pH range on beech-wood xylan was 4.5 to 9.5 (pH_opt 7.0-8.0). Fsa024940Xyn had a K_m of 2.375 mm, V_max of 1250 μm·min^-1, and k_cat/K_m of 1.2FEBS open bioCharacterization of the thermophilic xylanase Fsa02490Xyn from the hyperthermophile Fervidibacter sacchari belonging to glycoside hydrolase family 10.PMC12485897HRD‐1712523DE-AC02-05CH1123180NSSC20M004380NSSC21M015780NSSC17K0548HRD-1712523DBI REU 1757316Mewalal RCovington JKBlaby IKNou NOTorosian NHess MPalmer MHedlund BPCook AMCheng JFHarmon-Smith MfalseCharacterization of the thermophilic xylanase Fsa02490Xyn from the hyperthermophile Fervidibacter sacchari belonging to glycoside hydrolase family 10.Fervidibacter sacchari is an aerobic hyperthermophile belonging to the phylum Armatimonadota that degrades a variety of polysaccharides. Its genome encodes 117 enzymes with one or more annotated glycoside hydrolase (GH) domain, but the roles of these putative GHs in polysaccharide catabolism are poorly defined. Here, we describe one F. sacchari enzyme encoding a GH10 domain, Fsa02490Xyn, that was previously shown to be active on Miscanthus, oat β-glucan, and beech-wood xylan, with optimal activity at 90-100 °C. We show that Fsa02490Xyn is also active on birch-wood xylan and gellan gum. The pH range on beech-wood xylan was 4.5 to 9.5 (pH_opt 7.0-8.0). Fsa024940Xyn had a K_m of 2.375 mm, V_max of 1250 μm·min^-1, and k_cat/K_m of 1.22025-01-01T00:00:00Z2025 Oct2026-06-04T00:22:47.741Z2026-05-03T03:12:31.54ZS-EPMC124858974088012410.1002/2211-5463.70072