REEVALUATING THE CLASSIFICATION OF HALOBACTEROIDES AND HALOANAEROBACTER SPECIES BASED ON SEQUENCE COMPARISONS OF THE 16S RIBOSOMAL-RNA GENE

The 16S rRNA gene (rDNA) sequence analysis of four halophilic anaerobe s: Halobacteroides halobius, H. lacunaris, Haloanaerobacter (Hb.) chit inovorans and H. acetoethylicus confirmed that they were all members o f the family Haloanaerobiaceae. H. lacunaris and H. halobius were foun d to be more closely related to each other and were distantly related to Sporohalobacter lortetti and the members of the genera Haloanaerobi um and Halothemothrix. These data are in agreement with their assignme nt to the genus Halobacteroides. Further analysis indicated that Hb, c hitinovorans was closely affiliated to members of the genus Halobacter oides, and therefore we propose to transfer it to the genus Halobacter oides as H. chitinovorans comb. nov, This transfer would invalidate th e genus Haloanaerobacter, as Hb. chitinovorans is the only member of t his genus. The 16S rDNA sequence analysis of H. acetoethylicum indicat ed that it was very closely related to members of the genus Haloanaero bium, viz. Haloanaerobium (Ha.) praevalens, Ha, salsugo, and Ha. alcal iphilum, and hence we propose to transfer it to the genus Haloanaerobi um as Ha. acetoethylicus comb, nov.