Peribacillus

Members of the genus Peribacillus are either aerobic or facultatively anaerobic and demonstrate endospore formation under adverse environmental or nutritional conditions. Most species have been isolated from either soil or human/animal guts. Peribacillus are usually motile, except in some cases when cells form and grow in chains. Peribacillus can survive in temperatures ranging from 3 °C to 45 °C, but optimal growth occurs in the range of 25-37 °C. Peribacillus butanolivorans is used in industrial processes, specifically in the remediation of butanol.[10]

Genomic analyses have identified three conserved signature indels (CSIs) in the proteins HAMP domain-containing protein, phospho-N-acetylmuramoyl-pentapeptide-transferase and stage II sporulation protein E, which are specific for members of the genus Peribacillus and provide molecular means to distinguish members of this genus from other Bacillaceae genera and bacteria.[1]

As of May 2021, there are a total of 17 species with validly published names in the genus Peribacillus.[3] Members of this genus group together and forms a monophyletic branch in phylogenetic trees created from concatenated sequences from conserved proteins, 16S rRNA gene sequences as well as the phylogenetic tree in the Genome Taxonomy Database (GTDB).[1][11]

Additional phylogenetic studies have identified a number of non-validly published species ("Bacillus cihuensis", "Bacillus massiliglaciei", "Bacillus massilioanorexius", "Bacillus massiliogorillae" and "Bacillus testis") that are considered to be members of this genus as they branch with other members of Peribacillus in phylogenetic trees and share the same unique molecular markers (specifically conserved signature indels).[9] However, transfer of these species into Peribacillus was not proposed due to the lack of strain culture information demonstrating the need for future analyses of this clade as more information become available.