Description of Gluconacetobacter swingsii sp nov and Gluconacetobacter rhaeticus sp nov., isolated from Italian apple fruit

Two Gram-negative, rod-shaped, non-spore-forming bacteria (DST GL01(T) and DST GL02(T)) were isolated from apple fruit juice in the region of the Italian Alps. On the basis of 16S rRNA gene sequence similarities, strains DST GL01(T) and DST GL02(T) were shown to belong to the a-subclass of the Proteobacteria, and, in particular, to the genus Gluconacetobacter, in the Gluconacetobacter xylinus branch (98(.)5-100%). Chemotaxonomic data (major ubiquinone, 010; predominant fatty acid, C-18:1 omega 7c, accounting for approximately 50% of the fatty acid content) support the affiliation of both strains to the genus Gluconacetobacter. The results of DNA-DNA hybridizations, together with physiological and biochemical data, allowed genotypic and phenotypic differentiation between strains DST GL01(T) and DST GL02(T) and from the 11 validly published Gluconacetobacter species. They therefore represent two new species, for which the names Gluconacetobacter swingsii sp. nov. and Gluconacetobacter rhaeticus sp. nov. are proposed, with the type strains DST GL01(T) (=LMG 22125(T)=DSM 16373(T)) and DST GL02(T) (=LMG 22126(T)=DSM 16663(T)), respectively.