Zhengella sedimenti sp. nov. and Phycobacter sedimenti sp. nov., two novel bacteria isolated from coastal sediment with genomic and metabolic analysis.

In this study, two novel Gram-stain-negative bacterial strains, K97 and ZM62, were isolated from sediment samples collected along the coast of Weihai, China, and described using polyphasic taxonomic techniques. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain K97 exhibited the highest sequence similarity (98.34%) with Phycobacter azelaicus F10 within the genus Phycobacter, followed by Pseudooceanicola marinus AZO-C (97.14%) and Phaeobacter italicus LMG24365 (96.85%). Strain ZM62 exhibited the highest sequence similarity (98.53%) with Zhengella mangrovi X9-2-2 within the genus Zhengella, followed by Phyllobacterium myrsinacearum NBRC 100019 (96.49%) and Oricola thermophila MEBiC13590 (96.35%). The respiratory quinone was Q-10 for both strains. The major fatty acid in both strains K97 and ZM62 is Summed Feature 8 (Cω6c/Cω7c). The main polar lipids for strain K97 included diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), and phosphatidylglycerol (PG), while for strain ZM62, the main polar lipids included diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), and phosphatidylcholine (PC). Based on the polyphasic taxonomic data, strain K97 is proposed as a novel species within the genus Phycobacter, for which the name Phycobacter sedimenti is proposed, and the type strain is K97 (= KCTC 8365 = MCCC 1H01460). Strain ZM62 is proposed as a novel species within the genus Zhengella, for which the name Zhengella sedimenti is proposed, and the type strain is ZM62 (= KCTC 8813 = MCCC 1H01495). Additionally, genomic and metabolic analyses revealed that the genus Phycobacter possesses DMSP synthesis and metabolism genes and a complete CMP-KDO pathway, indicating potential symbiosis with algae. Metabolic analysis of strain ZM62 indicates its potential role in the degradation of xenobiotic compounds, supported by the presence of annotated pathways for aminobenzoate (ko00627) and toluene (ko00623) degradation.