Division of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, B-3001 Heverlee, Belgium.
Institut Pascal, Université Clermont Auvergne, Avenue Blaise Pascal 4, F-63178 Aubiére cedex, France.
Int J Syst Evol Microbiol. 2023 May;73(5). doi: 10.1099/ijsem.0.005893.
Strain MDTJ8 is a chain-elongating thermophilic bacterium isolated from a thermophilic acidogenic anaerobic digestor treating human waste while producing the high commodity chemical -caproate. The strain grows and produces formate, acetate, -butyrate, -caproate and lactate from mono-, di- and polymeric saccharides at 37-60 °C (optimum, 50-55 °C) and at pH 5.0-7.0 (optimum, pH 6.5). The organism is an obligate anaerobe, is motile and its cells form rods (0.3-0.5×1.0-3.0 µm) that stain Gram-positive and occur primarily as chains. Phylogenetic analysis of both the 16S rRNA gene and full genome sequence shows that strain MDTJ8 belongs to a group that consists of mesophylic chain-elongating bacteria within the family , being nearest to EA1 (94.8 %) and BS-1 (93.7 %). Its genome (1.96 Mbp) with a G+C content of 49.6 mol% is remarkably smaller than those of other chain-elongating bacteria of the family . Pairwise average nucleotide identity and DNA-DNA hybridization values between strain MDJT8 and its mesophilic family members are less than 70 and 35 %, respectively, while pairwise average amino acid identity values are less than 68 %. In addition, strain MDJT8 uses far less carbohydrate and non-carbohydrate substrates compared to its nearest family members. The predominant cellular fatty acids of strain MDTJ8 are C, C DMA (dimethyl acetal) and C, while its polar lipid profile shows three unidentified glycophospholipids, 11 glycolipids, 13 phospholipids and six unidentified lipids. No respiratory quinones and polyamines are detected. Based on its phylogenetic, genotypic, morphological, physiological, biochemical and chemotaxonomic characteristics, strain MDTJ8 represents a novel species and novel genus of the family and gen. nov., sp. nov. is proposed as its name. The type strain is MDTJ8 (=DSM 114174=LMG 32615=NCCB 100883).
链延伸嗜热菌 MDTJ8 是从处理人类废物的嗜热产酸厌氧消化器中分离出来的，该菌在生产高商品化学品己酸的同时，也能生长并产生甲酸盐、乙酸盐、正丁酸盐、己酸盐和乳酸盐。该菌能利用单糖、二糖和多糖在 37-60°C（最佳温度为 50-55°C）和 pH5.0-7.0（最佳 pH 值为 6.5）的条件下生长和产酸。该菌是一种严格厌氧菌，具有运动性，其细胞呈杆状（0.3-0.5×1.0-3.0μm），革兰氏阳性，主要呈链状。16S rRNA 基因和全基因组序列的系统发育分析表明，MDTJ8 菌株属于中温链延伸菌科的一个群，与 EA1（94.8%）和 BS-1（93.7%）最为接近。其基因组（1.96 Mbp）GC 含量为 49.6mol%，明显小于该科其他链延伸菌。与中温亲缘菌株相比，MDTJ8 菌株的平均核苷酸同一性和 DNA-DNA 杂交值分别小于 70%和 35%，而平均氨基酸同一性值小于 68%。此外，与最接近的家族成员相比，MDTJ8 菌株使用的碳水化合物和非碳水化合物底物要少得多。MDTJ8 菌株的主要细胞脂肪酸为 C 、 C DMA（二甲缩醛）和 C ，其极性脂图谱显示三种未鉴定的糖脂、11 种糖脂、13 种磷脂和六种未鉴定的脂类。未检测到呼吸醌和多胺。基于其系统发育、基因型、形态学、生理学、生物化学和化学分类学特征，MDTJ8 代表了一个新的种和新的属，属于科和属，新属名建议为。模式株为 MDTJ8（=DSM 114174=LMG 32615=NCCB 100883）。
