Taxonomic Classification of Anoxybacillus Isolates from Geothermal Regions in Turkey by 16S rRNA Gene Sequences and ARDRA, ITS-PCR, Rep-PCR Analyses

Abstract

A total of 115 endospore-forming bacilli were taken for 16S rRNA gene sequence analyses and clustered among 7 genera. In this paper, the most abundant thermophiles belonging to genus Anoxybacillus with its 53 isolates are presented. The Anoxybacillus species, some of which were producing biotechnologically valuable enzymes, mostly displayed amylolytic and glucosidic activities and the ability of carbohydrate degradation made them superior in number among the other bacilli in these extreme habitats. In comparative sequence analyses, similarities ranged from 91.1% to 99.9% between the isolates and the type strains. Isolates were clustered into eight phylogenetic lineages within the type strains of A. kamchatkensis, A. flavithermus, A. kamchatchensis subsp. asaccharedens, and A. salavatliensis. In addition, C161ab and A321 were proposed as novel species which displayed < 97.0% similarities to their closest relatives. Moreover, their individual AluI, HaeIII, and TaqI ARDRA restriction patterns, ITS-, (GTG)5-, and BOX-PCR fingerprintings generated 27, 28, 31, 35, 40, and 41 clusters, respectively. The twelve type strains and 35 of the isolates showed unique distinctive patterns from all the others at least in two of these analyses. These phenotypic and genomic characters allowed us to differentiate their genotypic diversity from the reference strains.