Cellulomonas xiejunii sp. nov., Cellulomonas chengniuliangii sp. nov. and Cellulomonas wangsupingiae sp. nov., three cellulolytic bacteria isolated from intestinal contents of Marmota himalayana

Abstract

Six facultative anaerobic, Gram-stain-positive, oxidase-negative, rod-shaped bacteria (strains zg-B89T, zg-B12, zg-Y338T, zg-Y138, zg-Y908T and zg-Y766), were isolated from the intestinal contents of Marmota himalayana in Qinghai Province, PR China. The 16S rRNA gene sequence analysis showed that zg-B89T showed highest similarity to Cellulomonas iranensis NBRC 101100T (99.5 %), zg-Y338T to Cellulomonas cellasea DSM 20118T (98.7 %), and zg-Y908T to Cellulomonas flavigena DSM 20109T (99.0 %). Phylogenetic and phylogenomic analysis based on 16S rRNA gene and 881 core genes revealed that these six strains formed three separate clades in the genus Cellulomonas . Average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between these three novel species and all members of the genus Cellulomonas were below species thresholds (95–96 % for ANI and 70 % for dDDH). The DNA G+C contents of zg-B89T, zg-Y338T and zg-Y908T were 73.6, 72.9 and 74.5 %, respectively. Strains zg-B89T and zg-Y908T had anteiso-C15 : 0, C16 : 0 and anteiso-C15 : 1 A, and zg-Y338T had anteiso-C15 : 0, C16 : 0 and iso-C16 : 0 as the main fatty acids. All novel type strains had MK-9 (H4) as the predominant respiratory quinone, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside as the major polar lipids, and rhamnose, ribose and glucose as the cell-wall sugars. The peptidoglycan amino acids of zg-B89T, zg-Y338T and zg-Y908T contained ornithine, alanine, glutamic acid and aspartic acid (except for zg-Y338T). Based on genotypic, phenotypic, phylogenetic and biochemical properties, the six uncharacterized strains represent three novel species in the genus Cellulomonas , for which the names Cellulomonas xiejunii sp. nov. (type strain zg-B89T=GDMCC 1.2821T=KCTC 49756T), Cellulomonas chengniuliangii sp. nov. (type strain zg-Y338T=GDMCC 1.2829T=KCTC 49754T) and Cellulomonas wangsupingiae sp. nov. (type strain zg-Y908T=GDMCC 1.2820T=KCTC 49755T) are proposed, respectively.