Aquitalea pelogenes sp. nov., isolated from mineral peloid

Abstract

Strain P1297^T was isolated in the frame of a project aimed on the psychrotolerant microbiota occurring in water sources. The strain initially identified as a tentative species of the genus <i>Aeromonas</i> was rod-shaped, Gram-stain-negative, facultatively anaerobic and oxidase-positive. Subsequently, 16S rRNA gene sequence analysis placed strain P1297^T within the class <i>Betaproteobacteria</i> and showed <i>Aquitalea magnusonii</i> TRO-001DR8^T as the closest phylogenetic relative with 99.28 % 16S rRNA gene sequence similarity. Digital DDH and average nucleotide identity (ANI) were determined to evaluate the genomic relationship between strain P1297^T and <i>Aquitalea magnusonii</i> CCM 7607^T. Digital DDH estimation (31.3 ± 2.46 %) as well as ANI (85.6001 %; reciprocal value 85.3277 %) proved the dissimilarity of strain P1297^T. Further investigation using phenotyping, automated ribotyping, whole-cell protein profiling and PCR-fingerprinting methods showed a distinct taxonomic position of strain P1297^T among hitherto described species of the genus <i>Aquitalea</i>. DNA-DNA hybridization experiments revealed low binding values between strain P1297^T and <i>Aquitalea magnusonii</i> CCM 7607^T (57 ± 3 %) and <i>Aquitalea denitrificans</i> CCM 7935^T (41 ± 5 %). The DNA G+C content of strain P1297^T was 60.3 mol%. The predominant fatty acids were C_{16 : 1}ω7<i>c</i>/ iso-C_{15 : 0} 2-OH (47.0 %), C_{16 : 0} (24.5 %) and C_{18 : 1}ω7<i>c</i> (10.6 %), and the quinone system contained predominantly ubiquinone Q-8. The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified phospholipids and one unidentified aminophospholipid. Obtained results of genotypic and chemotaxonomic methods clearly proved that strain P1297^T represents a novel species of the genus <i>Aquitalea</i>, for which the name <i>Aquitalea pelogenes</i> sp. nov. is proposed. The type strain is P1297^T ( = CCM 7557^T = LMG 28989^T = CCUG 67440^T).