The underexplored halophilic genus Joostella within the Flavobacteriaceae family consists of only two species, both of which have received little attention for their potential biotechnological applications. In this study, we report the isolation and characterisation of a novel halophilic bacterium, strain CR20, using a genomic approach to investigate its biotechnological potential. Analysis of the 16S rRNA gene revealed that strain CR20 shares 97.5% and 96.2% sequence similarity with Joostella marina DSM 19592 T and Joostella atrarenae M1-2 T, respectively. Strain CR20 exhibited average nucleotide identity and digital DNA-DNA hybridisation values of 76.8-79.1% and 20.8-22.8%, respectively, with Joostella spp., which fall below the species delineation thresholds. Additionally, strain CR20 demonstrated average amino acid identity and percentage of conserved proteins values of 81.3-84.0% and 71.7-75.3%, respectively, with Joostella spp., above the genus delineation thresholds. Meanwhile, the average amino acid identity and percentage of conserved proteins values of strain CR20 against Galbibacter spp. are 73.9-80.0% and 61.3-72.3%, respectively, also above the genus delineation thresholds. These findings indicated strain CR20 has a close relationship with both genera. Chemotaxonomic analysis of strain CR20 identified predominant fatty acids, including iso-C17:0 3OH (25.3%), iso-C15:0 (14%), and C16:1 ω6c/C16:1 ω7c (12.2%). The assembled genome comprises 62 contigs, with a size of approximately 3,168,727 bp and a G + C content of 35.1%. Among 2,804 predicted genes, 2,559 were classified into 25 COG functional groups. A total of 68 genes with potential industrial applications were identified, including 1 β-mannanase, 2 β-xylosidases, 1 polysaccharide deacetylase, 4 other hemicellulases, 6 β-glucosidases, 25 proteases, and 29 phosphate-solubilising enzymes. Hydrolytic assays confirmed that strain CR20 produces these enzymes extracellularly. These findings highlight strain CR20 has potential for industrial applications.
To date, there is sparse information for the genus Robertkochia with Robertkochia marina CC-AMO-30DT as the only described member. We report here a new species isolated from mangrove soil collected at Malaysia Tanjung Piai National Park and perform polyphasic characterization to determine its taxonomic position. Strain CL23T is a Gram-negative, yellow-pigmented, strictly aerobic, catalase-positive and oxidase-positive bacterium. The optimal growth conditions were determined to be at pH 7.0, 30-37 °C and in 1-2 % (w/v) NaCl. The major respiratory quinone was menaquinone-6 (MK-6) and the highly abundant polar lipids were four unidentified lipids, a phosphatidylethanolamine and two unidentified aminolipids. The 16S rRNA gene similarity between strain CL23T and R. marina CC-AMO-30DT is 96.67 %. Strain CL23T and R. marina CC-AMO-30DT clustered together and were distinguished from taxa of closely related genera in 16S rRNA gene phylogenetic analysis. Genome sequencing revealed that strain CL23T has a genome size of 4.4 Mbp and a G+C content of 40.72 mol%. Overall genome related indexes including digital DNA-DNA hybridization value and average nucleotide identity are 17.70 % and approximately 70%, below the cutoffs of 70 and 95%, respectively, indicated that strain CL23T is a distinct species from R. marina CC-AMO-30DT. Collectively, based on the phenotypic, chemotaxonomic, phylogenetic and genomic evidences presented here, strain CL23T is proposed to represent a new species with the name Robertkochia solimangrovi sp. nov. (KCTC 72252T=LMG 31418T). An emended description of the genus Robertkochia is also proposed.