<i>Anaerococcoides</i><i>asporogena</i> gen. nov., sp. nov., a Strictly Anaerobic Bacterium, Isolated from the Dehydrated Sludge of a Steel Factory's Wastewater Treatment Plant

A microbial community study using a culture-dependent method was conducted on dehydrated sludge collected from a steel factory's wastewater treatment plant. One isolate, designated QWL-01^T, was a strictly anaerobic, Gram-stain-negative, non-motile, non-spore-forming bacterium with coccoid cells measuring 0.6-0.9 μm in diameter. The growth of strain QWL-01^T was observed at 4-40 °C (optimum at 28-35 °C), pH 5.5-8.0 (optimum at pH 7.1), and a range of 0-3% NaCl (optimum at 0.5%). An analysis of the Biolog AN plate revealed positive carbon source utilization only for palatinose, α-ketovaleric acid, and pyruvic acid. The predominant fatty acids were iso-C_13:0 (17.0%), C_16:0 dimethyl acetal (12.0%), and anteiso-C_13:0 (9.2%). A 16S rRNA gene sequence analysis through BLASTN demonstrated that the nearest phylogenetic neighbors of the novel strain were <i>Youngiibacter multivorans</i> DSM 6139^T (93.82%) and <i>Proteiniclasticum ruminis</i> JCM 14817^T (93.75%). The genome size of strain QWL-01^T was 3.69 Mbp, with a G+C content of 50.8 mol%. Comparing strain QWL-01^T with closely related species of genera <i>Proteiniclasticum</i> and <i>Youngiibacter</i>, the digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI), and average amino acid identity (AAI) values ranged from 26.60% to 36.80%, 65.89% to 68.30%, and 49.27% to 51.58%, respectively. Based on phenotypic, physiological, phylogenetic, and genomic relatedness evidence, strain QWL-01^T represents a novel genus in the family <i>Clostridiaceae</i>, for which the name <i>Anaerococcoides asporogena</i> gen. nov. sp. nov. is proposed. Strain QWL-01^T (=BCRC 81396^T = CICC 25258^T = NBRC 117088^T) is the type strain of the proposed novel species.