Terrimicrobium sacchariphilum gen. nov., sp nov., an anaerobic bacterium of the class 'Spartobacteria' in the phylum Verrucomicrobia, isolated from a rice paddy field

A strictly anaerobic, mesophilic, carbohydrate-fermenting bacterium, designated NM-5(T), was isolated from a rice paddy field. Cells of strain NM-5T were Gram-stain-negative, non-motile, non-spore-forming, short rods (0.5-0.7 mu mx0.6-1.2 mu m). The strain grew optimally at 37 degrees C (growth range 20-40 degrees C) and pH 7.0 (pH 5.5-8.0). The strain could grow fermentatively on arabinose, xylose, fructose, galactose, glucose, ribose, mannose, cellobiose, lactose, maltose and sucrose. The main end-products of glucose fermentation were acetate and propionate. Organic acids, alcohols and amino acids were not utilized for growth. Yeast extract was not required but stimulated the growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite, and Fe (III) nitrilotriacetate were not used as terminal electron acceptors. The DNA G+C content was 46.3 mol%. The major cellular fatty acids were iso-C-14:0, C-18:0 and C-16:0. 16S rRNA gene sequence analysis revealed that strain NM-5T belongs to the class 'Spartobacteria', subdivision 2 of the bacterial phylum Verrucomicrobia. Phylogenetically, the closest species was 'Chthoniobacter flavus' (89.6% similarity in 16S rRNA gene sequence). A novel genus and species, Terrimicrobium sacchariphilum gen. nov., sp. nov., is proposed. The type strain of the type species is NM-5(T) (=JCM 17479(T)=CGMCC 1.5168(T)).