Identification of acetic acid bacteria through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and report of Gluconobacter nephelii Kommanee et al. 2011 and Gluconobacter uchimurae Tanasupawat et al. 2012 as later heterotypic synonyms of Gluconobacter japonicus Malimas et al. 2009 and Gluconobacter oxydans (Henneberg 1897) De Ley 1961 (Approved Lists 1980) emend. Gosselé et al. 1983, respectively.

The classification and identification of acetic acid bacteria (AAB) underwent much change during the last two decades. However, several closely related AAB species are difficult to differentiate and rapid and correct species level identification remains challenging. In the present study, 281 well-characterized AAB strains representing AAB species of the family Acetobacteraceae were used to construct a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) identification database. The database was evaluated using 270 poorly characterized AAB strains. 16S rRNA and/or multilocus gene sequence analysis and whole-genome sequencing for the calculation of average nucleotide identity values were performed on a selection of strains to verify the accuracy of the obtained results. Virtually all poorly characterized AAB strains were accurately identified to the species level. Most of the remaining strains were considered to represent novel AAB species or belonged to species represented by too few strains in the identification database. The data also revealed that Gluconobacter nephelii and Gluconobacter uchimurae are later heterotypic synonyms of Gluconobacter japonicus and Gluconobacter oxydans, respectively.