Open AccessCapillibacterium thermochitinicola gen. nov., sp. nov., a novel anaerobic thermophilic chitinolytic bacterium from compost
Author(s) -
Umbhorn Ungkulpasvich,
Sirilak Baramee,
Ayaka Uke,
Akihiko Kosugi
Publication year - 2021
Publication title -
international journal of systematic and evolutionary microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 173
eISSN - 1466-5034
pISSN - 1466-5026
DOI - 10.1099/ijsem.0.004693
Subject(s) - biology , thermophile , 16s ribosomal rna , maltose , chitin , microbiology and biotechnology , firmicutes , bacteria , strain (injury) , cellobiose , sucrose , botany , food science , biochemistry , cellulose , cellulase , genetics , anatomy , chitosan
A novel Gram-negative, spore forming, obligately anaerobic, thermophilic, chitin-degrading bacterium, designated UUS1-1 T , was isolated from compost on Ishigaki Island, Japan by enrichment culturing using chitin powder as the carbon source. The strain has unique, long, hair-like rod morphological features and exhibits strong degradation activity toward crystalline chitin under thermophilic conditions. Growth of the novel strain was observed at 45–65 °C (optimum, 55 °C) and pH 6.5–7.5 (optimum, pH 7.0). In addition to chitin, the strain utilized several other carbon sources, including N -acetylglucosamine, glucose, galactose, mannose, maltose, cellobiose, fructose and sucrose. The end products of chitin degradation were acetate, lactate, H 2 and CO 2 . Phylogenetic tree analysis based on 16S rRNA gene sequences revealed a clear affiliation of the proposed bacterium to the phylum Firmicutes ; the most closely related species were Hydrogenispora ethanolica LX-B T and Desulfotomaculum thermobenzoicum DSM6193 T with similarities of 90.4 and 87.8 %, respectively. The G+C content of the genomic DNA was 52.1 mol%. The average nucleotide identity and digital DNA–DNA hybridization values between the genomes of UUS1-1 T and H. ethanolica LX-B T were 65.5 and 21.0 %, respectively. The cellular fatty acid composition of the strain was C 16 : 0 , anteiso-C 15 : 0 , C 14 : 0 , C 12 : 0 3-OH and dimethyl acetal-C 13 : 0 . Based on phenotypic, chemotaxonomic and genotypic analysis, strain UUS1-1 T represents a novel genus and species, for which the name Capillibacterium thermochitinicola gen. nov., sp. nov. is proposed. The type strain is UUS1-1 T (=JCM 33882 T =DSM 111537 T ).