Abstract

We isolated and analyzed a novel, Gram-stain-positive, aerobic, rod-shaped, non-motile actinobacterium, designated as strain ZFBP1038(T), from rock sampled on the north slope of Mount Everest. The growth requirements of this strain were 10-37 °C, pH 4-10, and 0-6% (w/v) NaCl. The sole respiratory quinone was MK-9, and the major fatty acids were anteiso-C(15:0) and iso-C(17:0). Peptidoglycan containing meso-diaminopimelic acid, ribose, and glucose were the major cell wall sugars, while polar lipids included diphosphatidyl glycerol, phosphatidyl glycerol, an unidentified phospholipid, and an unidentified glycolipid. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain ZFBP1038(T) has the highest similarity with Spelaeicoccus albus DSM 26341( T) (96.02%). ZFBP1038(T) formed a distinct monophyletic clade within the family Brevibacteriaceae and was distantly related to the genus Spelaeicoccus. The G + C content of strain ZFBP1038(T) was 63.65 mol% and the genome size was 4.05 Mb. Digital DNA-DNA hybridization, average nucleotide identity, and average amino acid identity values between the genomes of strain ZFBP1038(T) and representative reference strains were 19.3-25.2, 68.0-71.0, and 52.8-60.1%, respectively. Phylogenetic, phenotypic, and chemotaxonomic characteristics as well as comparative genome analyses suggested that strain ZFBP1038(T) represents a novel species of a new genus, for which the name Saxibacter gen. nov., sp. nov. was assigned with the type strain Saxibacter everestensis ZFBP1038(T) (= EE 014( T) = GDMCC 1.3024( T) = JCM 35335( T)).

• Keywords: Trichoderma reesei;Saxibacter everestensis;Comparative genomics;biofuels;biomass conversion;Mount Everest;Novel species;cbh1;cbh2;Polyphasic taxonomy