Aquibaculum arenosum gen. nov., sp. nov., a novel member of the family Rhodovibrionaceae, isolated from sea sand.

A Gram-negative, non-motile, and creamy-white coloured bacterium, designated CAU 1616T, was isolated from sea sand collected at Ayajin Beach, Goseong-gun, Republic of Korea. The bacterium was found to grow optimally at 37 °C, pH 8.0-8.5, and with 1-5 % (w/v) NaCl. Phylogenetic analyses based on the 16S rRNA gene sequences placed strain CAU 1616T within the order Rhodospirillales. The highest 16S rRNA gene sequence similarity was to Fodinicurvata fenggangensis YIM D812T (94.1 %), Fodinicurvata sediminis YIM D82T (93.7 %), Fodinicurvata halophila BA45ALT (93.6 %) and Algihabitans albus HHTR 118T (92.3 %). Comparing strain CAU 1616T with closely related species (Fodinicurvata fenggangensis YIM D812T and Fodinicurvata sediminis YIM D82T), the average nucleotide identity based on blast+ values were 69.7-69.8 %, the average amino acid identity values were 61.3-61.4 %, and the digital DNA-DNA hybridization values were 18.4-18.5 %. The assembled draft genome of strain CAU 1616T had 29 contigs with an N50 value of 385.8 kbp, a total length of 3 490 371 bp, and a DNA G+C content of 65.1 mol%. The predominant cellular fatty acids were C18 : 1 2-OH, C19 : 0 cyclo ω8c, and summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c). The major respiratory quinone was Q-10. Based on phenotypic, phylogenetic, and chemotaxonomic evidence, strain CAU 1616T represents a novel genus in the family Rhodovibrionaceae, for which the name Aquibaculum arenosum gen. nov., sp. nov. is proposed. The type strain is CAU 1616T (=KCTC 82428T=MCCC 1K06089T).

Description of Roseibium sediminicola sp. nov. Isolated from Sediment of a Tidal Flat on the Yellow Sea Coast.

A Gram-stain-negative, aerobic, rod-shaped, motile, flagellated bacterial strain, designated as CAU 1639T, was isolated from the tidal flat sediment on the Yellow Sea in the Republic of Korea. Growth of the isolate was observed at 20-37 °C, at pH 5.0-10.5 and with 0-7% (w/v) NaCl. The genomic DNA G + C content was 60.8%. Phylogenetic analysis, grounded on 16S rRNA gene sequencing, revealed that strain CAU 1639T was closely related to species within the genus Roseibium. It shared the highest similarity with Roseibium album CECT 5095T, followed by Roseibium aggregatum IAM 12614T and Roseibium salinum Cs25T, with 16S rRNA gene sequence similarity ranging from 98.0-98.4%. It was observed that the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values ranged between 72.5-79.5 and 20.0-22.9%, respectively. The polyphasic taxonomic analysis reveals that strain CAU 1639T represents a novel species in the genus Roseibium with the proposed name Roseibium sediminicola sp. nov. The type strain is CAU 1639T (= KCTC 82430T = MCCC 1K06081T).