J. Gen. Appl. Microbiol., 53, 259–264 (2007)

duced in acetic acid bacteria with a single species, Asaia bogorensis Yamada et al. 2000 (Yamada et al., 2000). Since the second and the third species were additionally described as Asaia siamensis Katsura et al. 2001 and Asaia krungthepensis Yukphan et al. 2004, three species were described in total (Katsura et al., 2001; Yukphan et al., 2004). Strains of the three Asaia species show common phenotypic features such as no or very weak oxidation of ethanol to acetic acid and no or very weak growth in the presence of 0.35% acetic acid (v/v). The discrimination of the three Asaia species from one another is mainly based on phenotypic features, e.g., acid production from and growth on different carbon compounds, which sometimes give unreliable conclusions in their identification and classification. We reported, as the second model, that the 16S23S rDNA ITS restriction analysis using two restriction endonucleases TaqI and MvaI is applicable to specieslevel identification and classification of thirteen strains randomly selected from a large number of Thai isolates assigned to the genus Asaia (Yukphan et al., 2006a). However, the thirteen strains tested did not give three restriction groups, which corresponded to the above-mentioned three Asaia species, but six restriction groups were given. In addition, a phylogenetic tree based on 16S-23S rDNA ITS sequences represented complicated clustering, which was composed of eight clusters. In a subsequent study, the 16S rDNA restriction analysis using three restriction endonucleases StyI, BsaJI, and SnaBI gave four restriction groups in regard to the three Asaia species for the selected thirteen strains mentioned above (Yukphan et al., 2006b). In a Identification of Thai isolates assigned to the genus Asaia based on 16S rDNA restriction analysis