Aquiflexum gelatinilyticum sp. nov., isolated from river water

Two Gram- stain-negative, strictly aerobic, rod-shaped, non-motile and non-gliding bacteria, designated as XJ19- 10T and XJ19-11, were isolated from river water in Xinjiang Uygur Autonomous Region, PR China. Cells of these strains were catalase-, oxidase-and gelatinase-positive and contained carotenoids but no flexirubins. Growth occurred at 10-30 degrees C, pH 7.0-9.0 and with 0-2.5% (w/v) NaCl. On the basis of the results of 16S rRNA gene sequence and genome analyses, the two isolates rep-resented members of the genus Aquiflexum, and the closest relative was Aquiflexum aquatile Z0201T with 16S rRNA gene sequence pairwise similarities of 97.9-98.1%. Furthermore, the average nucleotide identities and digital DNA-DNA hybridi-zation identities between the two isolates and other relatives were all less than 82.9 and 28.2 %, respectively, all below the species delineation thresholds. The results of pan-genomic analysis indicated that the type strain XJ19- 10T shared 2813 core gene clusters with other three type strains of members of the genus Aquiflexum, as well as having 623 strain-specific clusters. The major polar lipids were phosphatidylethanolamine, phosphatidylcholine, an unidentified aminolipid and unidentified lipids. The predominant fatty acids (>10% of the total contents) were iso-C15 : 0, iso-C15 :1G, iso-C17 : 0 3 -OH and summed feature 9, and MK -7 was the respiratory quinone. On the basis of the results of phenotypic, physiological, chemotaxonomic and genotypic characterization, strains XJ19- 10T and XJ19- 11 are considered to represent a novel species, for which the name Aquiflexum gelatinilyticum sp. nov. is proposed. The type strain is XJ19- 10T (=CGMCC 1.19385T =KCTC 92266T).

Automated summary

Two novel strains of bacteria, named XJ19-10T and XJ19-11, were isolated from river water in Xinjiang Uygur Autonomous Region, China. Through phenotypic, genotypic, and chemotaxonomic analysis, it was determined that these strains represent a new species, Aquiflexum gelatinilyticum sp. nov.