Marine sponges host diverse microbial communities that play essential roles in nutrient cycling and host health. During a study of the microbiota of marine sponges from Taiwan, two Gram-stain-negative, motile and facultatively anaerobic strains, XeTr1 T and StTr2, were isolated from Xestospongia sp. and Stylissa carteri , respectively. Cells were rod-shaped and showed catalase and oxidase activities. Growth was observed at 15–37 °C, pH 6.0–9.0 and 1.0–3.0% (w/v) NaCl. Strains XeTr1 T and StTr2 contained ubiquinone-8 and ubiquinone-9 as major quinones and summed feature 3 (C 16:1 ω7c ), summed features 8 (C 18:1 ω7c ) and C 16:0 as major fatty acids. The major polar lipids identified in strains XeTr1 T and StTr2 were phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic analysis based on the 16S rRNA gene sequence placed strains XeTr1 T and StTr2 within the family Endozoicomonadaceae , forming a distinct lineage that shared 94% or less sequence homology with its closest relatives, including Endozoicomonas lisbonensis NE40 T , Endozoicomonas arenosclerae CBAS 572 T and Endozoicomonas montiporae CL-33 T . The average amino acid identity values were below the cutoff range for species of the same genus, supporting the placement of strains XeTr1 T and StTr2 as representing a novel genus within the family Endozoicomonadaceae . Distinct phenotypic and chemotaxonomic characteristics, combined with low sequence similarity and a clear phylogenetic separation from known genera, support the proposal of a novel genus and species in the family Endozoicomonadeae , for which the name Spongorhabdus nitratireducens gen. nov., sp. nov. is proposed. The type strain is XeTr1 T (=JCM 37577 T =UCCCB 249 T ).
Oliveira et al. (Tue,) studied this question.