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An anaerobic bacterial strain, designated strain M3/9 T , was isolated from a laboratory-scale biogas fermenter fed with maize silage supplemented with 5 % wheat straw. Cells were straight, non-motile rods, which stained Gram-negative. Optimal growth occurred between 30 and 40°C, at pH 7.5-8.5, and up to 3.9 % (w/v) NaCl was tolerated. When grown on peptone from casein and soymeal, strain M3/9 T produced mainly acetic acid, ethanol, and isobutyric acid. The major cellular fatty acids of the novel strain were C 16 : 0 and C 16 : 0 DMA. The genome of strain M3/9 T is 3757  330 bp in size with a G+C content of 38.45 mol%. Phylogenetic analysis allocated strain M3/9 T within the family Lachnospiraceae with Clostridium colinum DSM 6011 T and Anaerotignum lactatifermentans DSM 14214 T being the most closely related species sharing 57.86 and 56.99% average amino acid identity and 16S rRNA gene sequence similarities of 91.58 and 91.26 %, respectively. Based on physiological, chemotaxonomic and genetic data, we propose the description of a novel species and genus Anaeropeptidivorans aminofermentans gen. nov., sp. nov., represented by the type strain M3/9 T (=DSM 100058 T =LMG 29527 T ). In addition, an emended description of Clostridium colinum is provided.

Strain MD1 T is an anaerobic, Gram-stain-negative bacterium isolated from a lab-scale biogas fermenter fed with maize silage. It has a rod-shaped morphology with peritrichously arranged appendages and forms long chains of cells and coccoid structures. The colonies of MD1 T were white, circular, slightly convex and had a smooth rim. The isolate is mesophilic, displaying growth between 25 and 45 °C with an optimum at 40 °C. It grew at pH values of pH 6.7-8.2 (optimum, pH 7.1) and tolerated the addition of up to 1.5% (w/v) NaCl to the medium. The main cellular fatty acids of MD1 T are C 14:0 DMA and C 16:0 . Strain MD1 T fermented xylose, arabinose, glucose, galactose, cellobiose, maltose, maltodextrin10, lactose starch, and xylan, producing mainly 2-propanol and acetic acid. The genome of the organism has a total length of 4163427 bp with a G+C content of 38.5 mol%. The two closest relatives to MD1 T are Mobilitalea sibirica P3M-3 T and Anaerotaenia torta FH052 T with 96.44 or 95.8 % 16S rRNA gene sequence similarity and POCP values of 46.58 and 50.58%, respectively. As MD1 T showed saccharolytic and xylanolytic properties, it may play an important role in the biogas fermentation process. Closely related variants of MD1 T were also abundant in microbial communities involved in methanogenic fermentation. Based on morphological, phylogenetic and genomic data, the isolated strain can be considered as representing a novel genus in the family Lachnospiraceae , for which the name Variimorphobacter saccharofermentans gen. nov., sp. nov. (type strain MD1 T =DSM 110715 T =JCM 39125 T ) is proposed.