Acetobacter oryzoeni sp. nov., isolated from Korean rice wine vinegar

A Gram-stain-negative, obligately aerobic bacterium, designated strain B6(T), was isolated from rice wine vinegar in the Republic of Korea. Cells were non-motile and oval short rods showing catalase-positive and oxidase-negative activities. Growth was observed at 15-45 degrees C (optimum, 30 degrees C) and pH 3.5-8.0 (optimum, pH 5.5-6.5). Strain B6(T) contained summed feature 8 (comprising C-18(:1)omega 7c and/or C-18:0 omega 6c), and C-16:0 as major fatty acids and ubiquinone-9 was identified as the sole isoprenoid quinone. The G+C content of the genomic DNA calculated from the whole genome was 53.1 mol%. Strain BC was most closely related to Acetobacter pasteurianus LMG 1262(T) with very high 16S rRNA gene sequence similarity (100 %) and the strains formed a very close phylogenetic lineage together in phylogenetic trees based on 16S rRNA gene sequences. However, relatedness analyses based on concatenated amino acid sequences of 354 core genes and whole-cell MALDI-TOF profiles showed that strain B6(T) may form a distinct phyletic lineage from Acetobacter species. In addition, average nucleotide identity and in silico DNA-DNA hybridization values between strain B6(T) and the type strains of Acetobacter species were less than 93.3 and 51.4 %. respectively. The genomic features of strain B6(T) were also differentiated from those of closely related Acetobacter type strains. Based on the phenotypic, chemotaxonomic and genomic features, strain B6(T) clearly represents a novel species of the genus Acetobacter, for which the name Acetobacter oryzoeni sp. nov. is proposed. The type strain is B6(T) (=KACC 21201(T)=JCM 33371(T)).