Xinfangfangia humi sp. nov., isolated from soil amended with humic acid

Two slightly beige-pigmented, Gram-stain-negative, rod-shaped bacterial strains, IMT-291 T and IMT-297, were isolated from soil in a field located in Malvern, Alabama, USA. The source soil had been amended with humic acid and continuously used for the cultivation of worms used for fish bait. It is still conceivable that the source of the strains is from the humic acid amendment, although all attempts to isolate the novel phenotypes from the humic acid source have failed. The two strains were identical based on morphology, growth rate and subsequently by 16S rRNA gene sequences, but showed differences in genomic fingerprint patterns generated by rep-PCR. Phylogenetic analysis based on the 16S rRNA gene revealed a placement of the strain in a distinct cluster with Xinfangfangia soli (97.2 % 16S rRNA gene sequence similarity) and in close proximity to the genus Falsirhodobacter with highest 16S rRNA gene sequence similarity of 95.3 % to the type strain of Falsirhodobacter deserti. Sequence similarities to all other type strains were below 95.0 %. The chemotaxonomic analysis showed a clear similarity to the genus Xinfangfangia. The main cellular fatty acids of the strain were C18 : 1 ω7c, 11-methly-C18 : 1 ω7c and C16 : 0. The major quinone was ubiquinone Q-10. Phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidylcholine were predominant in the polar lipid profile. The polyamine pattern contained the major compound spermidine and moderate amounts of putrescine and cadaverine. The diamino acid of the peptidoglycan was meso-diaminopimelic acid. Based on phylogenetic, chemotaxonomic and phenotypic analyses we propose a new species of the genus Xinfangfangia, with the name Xinfangfangiahumi sp. nov. and strain IMT-291 T (=LMG 30636 T =CIP 111625 T =CCM 8858 T ) as type strain.