Systematic study of the genus Acetobacter with descriptions of Acetobacterindonesiensis sp nov., Acetobacter tropicalis sp nov., Acetobacter orleanensis (Henneberg 1906) comb. nov., Acetobacter lovaniensis (Frateur 1950) comb. nov., and Acetobacter estunensis (Carr 1958) comb. nov.

Thirty-one Acetobacter strains obtained from culture collections and 45 Ace tobacter strains isolated from Indonesian sources were investigated for the ir phenotypic characteristics, ubiquinone systems, DNA base compositions, a nd levels of DNA-DNA relatedness. Of 31 reference strains, six showed the p resence of ubiquinone 10 (Q-10). These strains were eliminated from the gen us Acetobacter. The other 25 reference strains and 45 Indonesian isolates w ere subjected to a systematic study and separated into 8 distinct groups on the basis of DNA-DNA relatedness. The known species, Acetobacter aceti, A. pasteurianus, and A. peroxydans are retained for three of these groups. Ne w combinations, A. orleanensis (Henneberg 1906) comb. nov., A. lovaniensis (Frateur 1950) comb. nov., and A. estunensis (Carr 1958) comb. nov. are pro posed for three other groups. Two new species, A. indonesiensis sp. nov. an d A. tropicalis sp. nov. are proposed for the remaining two. No Indonesian isolates were identified as A. aceti, A. estunensis, and A. peroxydans. Phy logenetic analysis on the basis of 16S rDNA sequences was carried out for r epresentative strains from each of the groups. This supported that the eigh t species belonged to the genus Acetobacter. Several strains previously ass igned to the species of A. aceti and A. pasteurianus were scattered over th e different species. It is evident that the value of DNA-DNA relatedness be tween strains comprising a new species should be determined for the establi shment of the species. Thus current bacterial species without data of DNA-D NA relatedness should be reexamined for the stability of bacterial nomencla ture.