Novel nitrogen-fixing Acetobacter nitrogenifigens sp. nov., isolated from Kombucha tea

Abstract

The four nitrogen-fixing bacteria so far described in the family Acetobacteraceae belong to the genera Gluconacetobacter and Acetobacter. Nitrogen-fixing bacterial strain RG1T was isolated from Kombucha tea and, based on the phylogenetic analysis of 16S rRNA gene sequence which is supported by a high bootstrap value, was found to belong to the genus Acetobacter. Strain RG1T differed from Acetobacter aceti, the nearest member with a 16S rRNA gene sequence similarity of 98.2 %, and type strains of other Acetobacter species with regard to several characteristics of growth features in culture media, growth in nitrogen-free medium, production of γ-pyrone from glucose and dihydroxyacetone from glycerol. Strain RG1T utilized maltose, glycerol, sorbitol, fructose, galactose, arabinose and ethanol, but not methanol as a carbon source. These results, along with electrophoretic mobility patterns of nine metabolic enzymes, suggest that strain RG1T represents a novel nitrogen-fixing species. The ubiquinone present was Q-9 and DNA G+C content was 64.1 mol%. Strain RG1T exhibited a low value of 2–24 % DNA–DNA relatedness to the type strains of related acetobacters, which placed it as a separate taxon. On the basis of this data, the name Acetobacter nitrogenifigens sp. nov. is proposed, with the type strain RG1T (=MTCC 6912T=LMG 23498T).