Proteiniphilum propionicum sp. nov., a novel member of the phylum Bacteroidota isolated from pit clay used to produce Chinese liquor.

A novel, Gram-stain-negative, rod-shaped, strictly anaerobic bacterium of genus Proteiniphilum of the phylum Bacteroidota, named strain JNU-WLY501 ^T , was isolated from pit clay used to produce strong aroma-type liquor in PR China. The genomic DNA G+C content and genome size of JNU-WLY501 ^T were 41.4 % and 3.9 Mbp, respectively. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that JNU-WLY501 ^T was closely related to Proteiniphilum acetatigenes DSM 18083 ^T (95.7 %) and Proteiniphilum saccharofermentans M3/6 ^T (94.9 %). The pairwise average nucleotide identity based on blast and average amino acid identity values of JNU-WLY501 ^T compared with Proteiniphilum saccharofermentans M3/6 ^T were 73.6 and 77.3 %, respectively, which both were lower than the threshold values for bacterial species delineation. The strain grew at 20-40 °C, with optimum growth at 37 °C. The pH range for growth was 5.4-9.1, with optimum growth at pH 7.5. The sodium chloride range for growth was 0.0-4.0 %, with optimum growth at 0 %. The strain did not use glucose, maltose, fructose or starch. Yeast extract, tryptone and peptone supported the growth of JNU-WLY501 ^T , and the main fermentation products were acetate and propionate. The predominant cellular fatty acids (>5 %) of JNU-WLY501 ^T were anteiso-C _15 : 0 (30.6 %), anteiso-C _17 : 0 (26.1 %), C _16 : 0 (7.7 %), iso-C _16 : 0 (5.0 %) and iso-C _17 : 0 (5.0 %). The respiratory quinone of JNU-WLY501 ^T was MK-5. On the basis of the morphological, physiological, biochemical, chemotaxonomic, genotypic and phylogenetic results, JNU-WLY501 ^T represents a novel species of the genus Proteiniphilum , for which the name Proteiniphilum propionicum sp. nov. is proposed. The type strain is JNU-WLY501 ^T (=GDMCC 1.2686 ^T =JCM 34753 ^T ).