Pukyongiella litopenaei gen. nov., sp. nov., a novel bacterium isolated from the gut content of a whiteleg shrimp Litopenaeus vannamei

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.

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).