Inconstantimicrobium mannanitabidum sp. nov., a novel member of the family Clostridiaceae isolated from anoxic soil under the treatment of reductive soil disinfestation

An obligately anaerobic bacterial strain (TW13 T ) affiliated with the family Clostridiaceae within the class Clostridia was isolated from an anoxic soil sample subjected to reductive soil disinfestation. Cells of the strain were stained Gram-positive and spore-forming straight rods with a polar flagellum. The strain was saccharolytic and decomposed polysaccharides (glucomannan, pectin, starch and xylan). The strain produced acetate, butyrate and H 2 as fermentation products from carbohydrates utilized. The major cellular fatty acids of strain TW13 T were C 18:1 ω7c dimethylacetal, C 16:0 and C 17:1 ω8c/C 17:2 (as summed feature). The most closely related species of strain TW13 T based on the 16S rRNA gene sequences was Inconstantimicrobium porci WCA-383-APC-5B T with a sequence identity of 96.3%. The next closely related species were all in the genus Clostridium with sequence identities of up to 95.9% (for the type species of the genus, Clostridium butyricum DSM 10702 T , 93.9%). The genome analysis of strain TW13 T indicated that the genome size was 4.64 Mb, and the genomic DNA G+C content was 30.3 mol%. Strain TW13 T had genes related to the production of acetate, butyrate and H 2 , degradation of polysaccharides (mannan, pectin, starch and xylan) and glycogen metabolism. The values of the average amino acid identity and the percentage of conserved proteins between the genomes of strain TW13 T and I. porci WCA-383-APC-5B T or C. butyricum DSM 10702 T were 67.6 and 50.5% or 62.9 and 43.0%, respectively. Based on the phylogenetic, genomic and phenotypic analyses, Inconstantimicrobium mannanitabidum sp. nov. in the family Clostridiaceae is proposed to accommodate strain TW13 T (= NBRC 112100 T = DSM 114758 T ).