Cellulomonas electrica sp. nov., isolated from an electrochemical enrichment culture

A Gram-positive, facultatively anaerobic, rod-shaped actinomycete bacterium, strain NTE-D12^T was isolated from the filtrate (< 0.22 μm pore size) of an electrochemical enrichment culture. The strain grew in R2A medium at 15–40 °C (optimum 30 °C), pH 6–8 (optimum pH 6), and in the presence of 0–6% NaCl (optimum 0%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain NTE-D12^T is closely related to Cellulomonas algicola TKZ-21^T (97.9%), Cellulomonas biazotea DSM 20112^T (97.5%), and Cellulomonas fimi DSM 20113^T (97.5%). Genome-based phylogenetic analysis indicated that the closest relative is Cellulomonas citrea AO-9^T. Orthologous average nucleotide identity (OrthoANI) and digital DNA–DNA hybridization (dDDH) values between strain NTE-D12^T and related species ranged from 75.40–76.73% and 20.2–21.0%, respectively, clearly below the species delineation thresholds. In contrast, average amino acid identity (AAI) and percentage of conserved proteins (POCP) values ranged from 68.33–70.89% and 58.33–62.26%, respectively, indicating affiliation within the genus Cellulomonas. The major polar lipids were diphosphatidylglycerol, phosphatidylinositol, aminoglycophospholipid, and glycophospholipid. The peptidoglycan type was A4β with L-Orn–D-Ser–D-Glu. The predominant cellular fatty acid was anteiso-C_15:0 (65.6%). The major quinone was menaquinone-10, distinguishing the strain from the other Cellulomonas species. The genomic DNA GC content was 73.1%. Based on phenotypic, phylogenetic, and chemotaxonomic characteristics, strain NTE-D12^T (= NBRC 115591^T = DSM 114595^T) represents a novel species of the genus Cellulomonas, for which the name Cellulomonas electrica sp. nov. is proposed.