A Gram-stain-negative, non-spore-forming, rod-shaped, obligately anaerobic bacterium, designated strain BP5GT, was isolated from the hindgut of a silver drummer (Kyphosus sydneyanus) fish collected from the Hauraki Gulf, New Zealand. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the isolate belonged to the family Lachnospiraceae in the phylum Bacillota and was most closely related to Anaerotignum propionicum with 94.06 % sequence identity. Isolate BP5GT grew on agar medium containing mannitol and fish gut fluid as carbon sources. Clear colonies of approximately 1 mm diameter of the isolate grew within a week at 20-28 °C (optimum, 28 °C) and pH 7.6-8.5 (optimum, pH 8.5). Strain BP5GT was very sensitive to NaCl and the optimal concentration for growth was 0.045 % (w/v). Acetate and propionate were the major fermentation products. The major cellular fatty acids were C12 : 0, C14 : 0, C15 : 0 and C16 : 0. The genome sequence of the isolate was determined. Its G+C content was 38.41 mol% and the 71.41 % average nucleotide identity of the BP5GT genome to its closest neighbour with a sequenced genome (A. propionicum DSM 1682T) indicated low genomic relatedness. Based on the phenotypic and taxonomic characteristics observed in this study, a novel genus and species named Chakrabartyella piscis gen. nov., sp. nov. is proposed for isolate BP5GT (=ICMP 24687T=JCM 35769T).
Keywords: Bacillota; Firmicutes; Lachnospiraceae; herbivorous fish; hindgut fermenter; seaweed.