Pseudoxanthomonas sacheonensis sp. nov., isolated from BTEX-contaminated soil in Korea, transfer of Stenotrophomonas dokdonensis Yoon et al. 2006 to the genus Pseudoxanthomonas as Pseudoxanthomonas dokdonensis comb. nov. and emended description of the genus Pseudoxanthomonas

Researchers isolated a novel bacterium designated strain BD-c54T from BTEX-contaminated soil in Sacheon, Korea. This Gram-negative, strictly aerobic, rod-shaped bacterium grows optimally at 25-30°C and pH 7.0-8.0. Phylogenetic analysis based on 16S rRNA gene sequences showed the strain clusters closely with Pseudoxanthomonas yeongjuensis, sharing 98.3% sequence similarity. DNA-DNA hybridization revealed only 24.5% relatedness to P. yeongjuensis, well below the 70% threshold for species designation, indicating BD-c54T represents a novel species. Chemotaxonomic analysis confirmed characteristics typical of the Pseudoxanthomonas genus, including predominant iso-branched fatty acids, ubiquinone-8 as the major quinone, and 67.5 mol% G+C content. The study proposes strain BD-c54T as Pseudoxanthomonas sacheonensis sp. nov. Additionally, the authors transfer Stenotrophomonas dokdonensis to the genus Pseudoxanthomonas based on phylogenetic and phenotypic evidence, designating it Pseudoxanthomonas dokdonensis comb. nov., and provide an emended description of the Pseudoxanthomonas genus.

Key findings

• Strain BD-c54T, isolated from BTEX-contaminated soil in Korea, represents a novel species within Pseudoxanthomonas, designated Pseudoxanthomonas sacheonensis sp. nov.
• Phylogenetic analysis based on 16S rRNA genes demonstrated BD-c54T forms a tight lineage with P. yeongjuensis (98.3% similarity) but DNA-DNA relatedness of only 24.5% confirms species-level distinction.
• Chemotaxonomic characteristics including branched-chain fatty acids, ubiquinone-8, and 67.5 mol% G+C content are consistent with the Pseudoxanthomonas genus.
• Stenotrophomonas dokdonensis is transferred to Pseudoxanthomonas genus as Pseudoxanthomonas dokdonensis comb. nov. based on phylogenetic positioning and phenotypic analysis.