Acidaminobacterium chupaoyuni gen. nov., sp. nov., a novel member of the family Oscillospiraceae isolated from pit clay for strong aroma-type liquor production

A novel, strictly anaerobic, Gram-positive, rod-shaped bacterium, designated strain LBM23126^T, was isolated from the pit clay of strong aroma-type liquor-making, exhibiting high temperature tolerance and lacking motility. LBM23126^T had a genome size of 2,416,380 bp and a G+C content of 52.5 mol%. The major fatty acid was C_{16 : 0} (16.46%). The polar lipids of strain LBM23126^T were composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, three glycolipids, nine phospholipids, two aminolipids, two aminophospholipids and six unidentified lipids. LBM23126^T thrived in a pH range from 6.0 to 8.5 (optimum, pH 7.0-8.0), a temperature from 30 °C to 40 °C (optimum, 35-40 °C) and a salt tolerance of 0-2 % (w/v) sodium chloride (optimum, 0%). Notably, this bacterium was unable to utilize common sugars like glucose, maltose and sucrose, making it unique within the family <i>Oscillospiraceae</i>. LBM23126^T can use pyruvate as the carbon source to produce acetic acid as the primary metabolic product. LBM23126^T grew well with yeast extract, beef extract and tryptone. Comparing the 16S rRNA gene sequence identities of LBM23126^T with other <i>Oscillospiraceae</i> members, LBM23126^T showed the closest relationship with <i>Intestinimonas butyriciproducens</i> SRB-521-5-I^T (91.94%) and followed by <i>Intestinimonas massiliensis</i> GD2^T (91.22%). The average nucleotide identity (ANIb) based on blastn values for strain LBM23126^T with <i>I. butyriciproducens</i> SRB-521-5-I^T and <i>I. massiliensis</i> GD2^T were 74.05 and 74.07 %, respectively. The average amino acid identity (AAI) values for strain LBM23126^T with <i>I. butyriciproducens</i> SRB-521-5-I^T and <i>I. massiliensis</i> GD2^T were 53.63 and 53.31 %, respectively, while the percentage of conserved proteins (POCP) was 35 and 34 %, respectively. The AAI and POCP values were all lower than the thresholds required for classifying a new genus. Based on morphology, physiology, biochemistry, genotypic characteristics and phylogenetic analysis, strain LBM23126^T represents a novel species of a novel genus of the family <i>Oscillospiraceae</i>, for which the name <i>Acidaminobacterium chupaoyuni</i> gen. nov., sp. nov. is proposed. The type strain is LBM23126^T (=GDMCC 1.4723^T=JCM 37290^T).