Re-examination of the genusThirty-four Acetobacter strains, representing Acetobacter aceti, Acetobacter pasteurianus, Acetobacter pomorum, Acetobacter peroxydans, Acetobacter lovaniensis, Acetobacter estunensis, Acetobacter orleanensis, Acetobacter indonesiensis and Acetobacter tropicalis, were subjected to a polyphasic study that included DNA-DNA hybridizations, DNA base ratio determinations, 16S rDNA sequence analysis and phenotypic characterization. Two novel species are proposed, Acetobacter cerevisiae sp. nov. and Acetobacter malorum sp. nov. The type strains of these species are respectively LMG 1625

Classification of metal-resistant bacteria from industrial biotopes as), respectively. Six isolates were allocated to Ralstonia basilensis, which presently contains only the type strain ; an emendation of the latter species description is therefore proposed.

Results of deoxyribonucleic acid (DNA)-ribosomal ribonucleic acid and DNA-DNA hybridizations, together with a phenotypic and chemotaxonomic analysis, revealed that nitrogen-fixing bacteria isolated from roots and stems of sugarcane belong to a new species in the genus Acetobacter, for which the name Acetobacter diazotrophicus sp. nov. is proposed. Strain LMG 7603 (= Dobereiner PA1 5 = ATCC 49037) is the type strain.New microaerobic, gram-negative, N,-fixing bacteria were isolated from roots and stems of sugarcane in Brazil (1). Because of their ability to grow at low pH values and their ability to form acetic acid from ethanol, these organisms could belong to the acetic acid bacteria (the genera Acetobacter and Gluconobacter) (3, 4) or to the genus Frateuria (14). However, Cavalcante and Dobereiner (1) believed that the differences between these genera and the N,-fixing sugarcane isolates were sufficiently great to propose the name "Saccharobacter nitrocaptans" (not validly published). The original description (1) was based on more than 20 strains isolated in four different regions of Brazil.In this paper we present genomic, phenotypic, and chemotaxonomic evidence that these isolates constitute a new species in the genus Acetobacter, for which we propose the name Acetobacter diazotrophicus.Details of the strains and their sources are given in Table 1. Cells for genomic studies, protein electrophoresis, and determination of ubiquinones were grown on GYC medium (5% glucose, 1% yeast extract, 3% CaCO,, 2.5% agar). The methods which we used have been described previously (2, 4, 6-12). Differentiating phenotypic tests were simultaneously carried out on all A. diazotrophicus strains listed in Table 1; the type strains of all Acetobacter species were included as controls.The protein electrophoretic fingerprints of the seven A . diazotrophicus strains are very similar, indicating that these sugarcane isolates are highly related to each other (Fig. l), yet the protein patterns of strains PR 14 and PR 2 are slightly different from those of the other sugarcane isolates. The levels of deoxyribonucleic acid (DNA) binding (as determined by the initial renaturation rate method [2]) among three representative A. diazotrophicus strains (strains PA 5T [T = type strain], PPe 4, and PR 2) were more than 84%, indicating that these strains form a single DNA homology group.DNA-ribosomal ribonucleic acid (rRNA) hybridizations revealed the generic status of the sugarcane isolates. A preliminary hybridization between DNA from strain PA 5T and 23s [14C]rRNA from Xanthomonas cumpestris NCPPB 52ST resulted in a T,,,(,) value (midpoint temperature of the thermal denaturation curve of the DNA-rRNA hybrid) of 55.6"C, demonstrating that the sugarcane isolates are not members of rRNA superfamily 11, which corresponds to the

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Fourteen homofermentative lactic acid bacteria that were isolated from kefir grains and kefir fermented milks were assigned to either Lactobacillus kefiranofaciens or Lactobacillus kefirgranum, based on their characteristic morphotypes, phenotypic features and SDS-PAGE profiles of whole-cell proteins. Further genotypic analyses on representative strains from both taxa demonstrated that L. kefiranofaciens and L. kefirgranum share 100 % 16S rDNA sequence similarity and belong phylogenetically to the Lactobacillus acidophilus species group. DNA–DNA binding values of >79 % and analogous DNA G+C contents of 37–38 mol% showed that the strains studied belonged to one species: L. kefirgranum is a later synonym of L. kefiranofaciens. An emended description is proposed for L. kefiranofaciens. Due to the specific morphological and biochemical characteristics of these taxa in kefir grain formation, it is proposed that L. kefirgranum should be reclassified as L. kefiranofaciens subsp. kefirgranum subsp. nov.