Brevilactibacter coleopterorum sp. Nov., isolated from the intestine of the dark diving beetle hydrophilus acuminatus, and weissella coleopterorum sp. nov., isolated from the intestine of the diving beetle cybister lewisianus

A polyphasic taxonomic approach was used to characterize two novel bacterial strains, designated as HDW11^T and HDW19^T, isolated from intestine samples of the dark diving beetle Hydrophilus acuminatus and the diving beetle Cybister lewisianus, respectively. Both isolates were Gram-stain-positive, facultatively anaerobic and non-motile. Strain HDW11^T grew optimally at 30 °C, pH 8 and in the presence of 1% (w/v) NaCl. Strain HDW19^T grew optimally at 25 °C, pH 7 and in the presence of 0.3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences and genome sequences revealed that strain HDW11^T is a member of the genus Brevilactibacter and is closely related to Brevilactibacter flavus VG341^T [with 97.9% 16S rRNA sequence identity and 79.1% average nucleotide identity (ANI)], and that strain HDW19^T belongs to the genus Weissella and is closely related to W. koreensis KCTC 3621^T (with 98.9% 16S rRNA sequence identity and 79.5% ANI). The major cellular fatty acids of strains HDW11^T and HDW19^T were C_18:1 ω9c and anteiso-C_15:0, respectively. The sole respiratory quinone of strain HDW11^T was MK-9 (H₄). The major polar lipid components of strain HDW11^T were diphosphatidylglycerol and phosphatidylglycerol, and the major polar lipid component of strain HDW19^T was diphosphatidylglycerol. The genomic DNA G+C content of strains HDW11^T and HDW19^T were 72.1 and 37.2 mol%, respectively. The results of phylogenetic, phenotypic, chemotaxonomic and genotypic analyses suggest that strain HDW11^T represents a novel species within the genus Brevilactibacter, and that strain HDW19^T represents a novel species within the genus Weissella. We propose the name Brevilactibacter coleopterorum sp. nov. for strain HDW11^T (=KACC 21335^T=KCTC 49320^T=JCM 33680^T) and the name Weissella coleopterorum for strain HDW19^T (=KACC 21347^T=KCTC 43114^T=JCM 33684^T).