Bacillus thermodenitrificans sp. nov., nom. rev.

Area of Science:

• Microbiology
• Bacterial Taxonomy
• Genomics

Background:

• Thermophilic denitrifying Bacillus strains are important in soil ecosystems.
• Accurate taxonomic classification is crucial for understanding bacterial roles.
• Previous studies suggested the existence of Bacillus thermodenitrificans.

Purpose of the Study:

• To polyphasically characterize 10 thermophilic denitrifying Bacillus soil isolates.
• To determine the taxonomic status of these isolates.
• To propose a formal designation for the species if warranted.

Main Methods:

• Polyphasic taxonomic study including molecular (ITS region amplification, DNA-DNA reassociation) and chemotaxonomic (fatty acid analysis) methods.
• Ribotyping for strain differentiation.
• Phylogenetic analysis based on collected data.

Main Results:

• Amplification of the internal transcribed spacer (ITS) region showed similarity to Bacillus thermodenitrificans.
• Ribotyping and fatty acid analyses indicated close relatedness among isolates and to B. thermodenitrificans strains.
• DNA-DNA reassociation studies revealed >73% genomic similarity between the isolates and B. thermodenitrificans DSM strains, confirming they belong to the same taxon.
• Lower DNA-DNA similarity (21-43%) was observed with related Bacillus species.

Conclusions:

• The 10 soil isolates are confirmed as strains of Bacillus thermodenitrificans.
• The designation of Bacillus thermodenitrificans sp. nov., nom. rev. is proposed.
• Strain DSM 465T is designated as the type strain for Bacillus thermodenitrificans.