Carideicomes alvinocaridis gen. nov., sp. nov., a marine bacterium isolated from shrimp gill in a hydrothermal field of Okinawa Trough

An Update on Novel Taxa and Revised Taxonomic Status of Bacteria (Including Members of the Phylum Planctomycetota) Isolated from Aquatic Host Species Described in 2018 to 2021

Increased interest in farmed aquatic species, aquatic conservation measures, and microbial metabolic end-product utilization have translated into a need for awareness and recognition of novel microbial species and revisions to bacterial taxonomy. Because this need has largely been unmet, through a 4-year literature review, we present lists of novel and revised bacterial species (including members of the phylum Planctomycetota) derived from aquatic hosts that can serve as a baseline for future biennial summaries of taxonomic revisions in this field. Most new and revised taxa were noted within oxidase-positive and/or nonglucose fermentative Gram-negative bacilli, including members of the Tenacibaculum, Flavobacterium, and Vibrio genera. Valid and effectively published novel members of the Streptococcus, Erysipelothrix, and Photobacterium genera are additionally described from disease pathogenesis perspectives.

Limibaculum sediminis sp. nov., isolated from mangrove sediment

A Gram-stain-negative, cream-coloured, aerobic, motile and ovoid- to rod-shaped bacterium, designated as FT325^T, was isolated from mangrove sediment collected in Shenzhen, PR China. The taxonomic position of strain FT325^T was established by phylogenetic, physiological, biochemical and chemotaxonomic analyses. Strain FT325^T grew optimally at 37-40 °C and pH 6.0 in the presence of 0 % (w/v) NaCl. Results of 16S rRNA gene sequence analysis showed that strain FT325^T was most similarly related to Limibaculum halophilum CAU 1123^T (96.2 %), Phaeovulum vinaykumarii DSM 18714^T (93.9%) and Amaricoccus solimangrovi HB 172011^T (93.7 %). The major fatty acids (>10 %) were C_18 : 1  ω7c (60.0 %) and 11-methyl C_18 : 1  ω7c (16.7 %). The sole respiratory quinone was Q-10. The polar lipids were phosphatidylglycerol, one unidentified glycolipid, three unidentified aminolipids and three unidentified phospholipids. Its estimated genome size was 4 318 768 bp and the genomic DNA G+C content was 69.6 mol%. Based on its distinct phenotypic, chemotaxonomic and phylogenetic characteristics, strain FT325^T represents a novel species of the genus Limibaculum, for which the name Limibaculum sediminis sp. nov. is proposed (=MCCC 1K07397^T=KCTC 92313^T).

Sedimentimonas flavescens gen. nov., sp. nov., isolated from sediment of Clam Island, Liaoning Province

A novel Gram-stain negative, aerobic and ovoid to short rod shaped bacterium with a single polar flagellum, named strain B57^T, was isolated from sediment of Clam Island, Liaoning Province, China. The optimal growth of this strain was found to occur at 37 °C, pH 6-6.5, and in the presence of 2% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain B57^T forms a distinct lineage within the family Rhodobacteraceae, sharing high 16S rRNA gene sequence similarity with Sinirhodobacter populi sk2b1^T (97.4%). The average amino acid identity of B57^T and the closely related species were lower than the threshold level for genus delineation. The dominant respiratory quinone of strain B57^T was identified as Q-10. The major fatty acids were found to be Summed Feature 8 (C_18:1ω7c and/or C_18:1ω6c), Summed Feature 3 (C_16:1ω7c and/or C_16:1ω6c) and C_16: 0. The polar lipids were identified as phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, diphosphatidylglycerol, two unidentified phospholipids, one unidentified glycolipid, and one unidentified lipid. The DNA G + C content of strain B57^T was determined to be 64.1 mol%. Based on the biochemical, phylogenetic and chemotaxonomic analysis, strain B57^T is concluded to represent a novel species of a novel genus, for which the name Sedimentimonas flavescens gen. nov., sp. nov.is proposed. The type strain is B57^T (= CGMCC1.19488^T = KCTC 92053^T).

Oceanomicrobium pacificus gen. nov., sp. nov., a member of the family Rhodobacteraceae isolated from seawater of tropical western Pacific

The Gram-stain-negative, aerobic, ovoid or rod-shaped bacterial strain, designated KN286^T, was isolated from seawater of tropical western Pacific. Growth occurred between 15 and 40 °C (optimally at 30-35 °C), pH 6-9 (optimally at 7.0) and in the presence of 0.5-5.0% (w/v) NaCl (optimally between 2.0 and 3.0%). Strain KN286^T contained Q-10 as the major respiratory quinone. The polar lipid profile contained phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, three phospholipids, three glycolipids, and three unidentified polar lipids. The predominant cellular fatty acid was summed feature 8 (composed of C_18:1ω7c and/or C_18:1ω6c). Phylogenetic analysis of the 16S rRNA gene sequence revealed that strain KN286^T was a member of the family Rhodobacteraceae and formed a distinct lineage. Strain KN286^T has a genome size of 3.25 Mbp and a G + C content of 65.0 mol%. It encoded with some genes for carbohydrate-active enzymes, such as GH20 (Glycoside Hydrolase Family 20) and PL1 (Polysaccharide Lyase Family 1) and did not encode with a set of genes for reduction of nitrate to nitrite (nitrate reductase gamma subunit, respiratory nitrate reductase alpha N-terminal and respiratory nitrate reductase beta C-terminal). Based on phylogenetic analyses with single-copy orthologous clusters, low isDDH value (19.6%), low ANI (72.4%) and low AAI (65.7%) results, differential chemotaxonomic and physiological properties, strain KN286^T represents a novel species of a novel genus of the family Rhodobacteraceae, for which the name Oceanomicrobium pacificus gen. nov., sp. nov. is proposed. The type strain of Oceanomicrobium pacificus is KN286^T (=CGMCC 1.17118^T = KCTC 72430^T).