Abstract
A strictly anaerobic, mesophilic and aminolytic strain (WN036T) was isolated from a methanogenic reactor treating waste from cattle farms. Cells were Gram-positive cocci, often occurred in pairs and were non-motile. Although spore formation was not confirmed by microscopic observation of cells, the strain produced thermotolerant cells. The optimum temperature for growth was 35–37 °C and the optimum pH was 6.7. Oxidase, catalase and nitrate-reducing activities were negative. The novel strain did not ferment carbohydrates and grew in PY medium without additional substrates. The strain utilized L-glutamate, L-glutamine, L-histidine and L-arginine as growth substrates. Major fermentation products were acetate and butyrate with a small amount of propionate. The genomic DNA G+C content was 32.5 mol%. The major cellular fatty acids were C17 : 1ω8, C18 : 1ω7 DMA and C16 : 0. The diagnostic diamino acid of the cell-wall peptidoglycan was lysine. Glutamic acid, glycine, alanine and aspartic acid were also detected in the cell-wall peptidoglycan. On the basis of 16S rRNA gene sequences, the most closely related species to strain WN036T were Peptoniphilus asaccharolyticus ATCC 14965T (89.8 %) and Peptoniphilus indolicus ATCC 29427T (89.6 %). Based on the differences in the phenotypic and phylogenetic characteristics of strain WN036T compared with those of closely related species, a novel genus and species, Anaerosphaera aminiphila gen. nov., sp. nov., is proposed. The type strain is WN036T (=JCM 15094T=DSM 21120T).