gen. nov., sp. nov., a new member of the family , isolated from a maize-fed biogas fermenter.

Strain MD1 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 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 are C DMA and C. Strain MD1 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 are P3M-3 and FH052 with 96.44 or 95.8 % 16S rRNA gene sequence similarity and POCP values of 46.58 and 50.58%, respectively. As MD1 showed saccharolytic and xylanolytic properties, it may play an important role in the biogas fermentation process. Closely related variants of MD1 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 , for which the name gen. nov., sp. nov. (type strain MD1=DSM 110715=JCM 39125) is proposed.