Proposal of a novel subspecies: Alicyclobacillus hesperidum subspecies aegles

Alicyclobacillus sp. DSM 11985 T was isolated from geothermal soil but had not yet been classified at the species level. The strain produced guaiacol, which is of interest from the viewpoint of food spoilage in the food industry. 16S rRNA gene sequence analysis revealed that strain DSM 11985 T was closely related (99.6 % similarity) to Alicyclobacillus hesperidum DSM 12489 T . However, strains of A. hesperidum did not produce guaiacol; therefore, we performed the taxonomic characterization of strain DSM 11985 T . The results showed that strain DSM 11985 T and strains of A. hesperidum showed different phenotypic characteristics in biochemical/physiological tests including guaiacol production. Average nucleotide identity values between strain DSM 11985 T and strain DSM 12489 T were 95.4–95.9 %, and the in silico DNA–DNA hybridization value using the Genome-to-Genome Distance Calculator between strains DSM 11985 T and DSM 12489 T was 65.5 %. These values showed that strain DSM 11985 T was genetically closely related but separated from strains of A. heparidum . From the above results, a novel subspecies of A. hesperidum , named Alicyclobacillus hesperidum subsp. aegles subsp. nov. is proposed. The type strain is DSM 11985 T (=FR-12 T =NBRC 113041 T ).