The great diversity of thermophilic bacteria related to the genus Bacillus has been emphasized frequently. The paucity of readily identifiable phenotypic characteristics useful for an unequivocal identification of these spore-formers (Sharp et al. 1992) had led to classification methods based on phylogenetic assessments. The comparison of restriction patterns of amplified 16S rDNA (ARDRA) is a simple method for clustering organisms in genetically homogeneous clusters (Vaneechoutte et al. 1992). Recently, ARDRA has been used successfully for a rapid and reliable identification of bacilli newly isolated from hot composts, soil samples and deep-sea thermal vents (Blanc et al. 1997, 1999; Mora et al. 1998; Jeanthon et al. 1999). All Bacillus reference species described so far were isolated from soil, compost, mud, air and water of terrestrial hot springs (Sharp et al. 1992; Andersson et al. 1995; Combet-Blanc et al. 1995; Meier-Stauffer et al. 1996; Blanc et al. 1997). Until recently, few were the reports about thermophilic bacilli inhabiting marine hot springs (Hjörleifsdóttir et al. ,989; Marteinsson et al. 1996). Recent studies on shallow, marine thermal vents of the Eolian Islands, Italy allowed isolation and characterization of thermophilic spore-formers which showed a high heterogeneity with respect to known thermophilic bacilli (Maugeri et al. 2000). Genotypic studies allowed recognition of six new thermophilic Bacillus species among these isolates, one of which has been described as B. vulcani (Caccamo et al. 2000).
In this paper, we report the rapid and reliable identification of thermophilic bacilli newly isolated from shallow, marine hydrothermal vents of the Eolian Islands by comparison of their amplified 16S rDNA restriction patterns with those of thermophilic Bacillus reference species.