Description of a moderately acidotolerant and aerotolerant anaerobic bacterium Acidilutibacter cellobiosedens gen. nov., sp. nov. within the family Acidilutibacteraceae fam. nov., and proposal of Sporanaerobacteraceae fam. nov. and Tepidimicrobiaceae fam. nov.

A Gram-stain positive, moderately thermophilic, acidotolerant and aerotolerant anaerobic bacterium, designated JN-28 , was isolated from the pit mud of Chinese strong-flavor liquor. Growth was observed at 25-50 °C and pH 5.5-8.0 in the presence of 0-25 g l NaCl (optimally at 45 °C, pH 6.0, without NaCl). Strain JN-28  was heterotrophic, requiring yeast extract for growth. The major cellular fatty acids were iso-C and C. The DNA G + C content of genomic DNA was 33.54 mol%. The strain was resistant to vancomycin (10 mg l). Genome analysis revealed the presence of genes involved in the response to mild acid stress and oxidative stress, and resistance to vancomycin. 16S rRNA gene-based phylogenetic analysis showed that strain JN-28  shares ≤ 89.3 % sequence similarity with its closest relatives Sporanaerobacter acetigenes DSM 13106  and other members in the order Tissierellales. Based on phenotypic and phylogenetic characteristics, Acidilutibacter cellobiosedens gen. nov., sp. nov. is proposed for the new genus and novel species with the type strain JN-28  (=CCAM 418  = JCM 39087 ). Further phylogenetic and phylogenomic analyses suggested strain JN-28  represents a novel family within the order Tissierellales, for which Acidilutibacteraceae fam. nov. is proposed. In addition, the family Tissierellaceae was reclassified, Sporanaerobacteraceae fam. nov. and Tepidimicrobiaceae fam. nov. were formally proposed. Emended description of the family Tissierellaceae is also provided.