Orrella
Résumé
Cells are nonmotile, non‐spore‐forming coccobacilli (0.9–1.1 µm). Gram‐negative. Strictly respiratory with oxygen or nitrate as terminal electron acceptor. The optimal temperature for growth is 15–30°C, feeble at 40°C; no growth at 42°C. Optimal growth occurs between pH 7 and 9; no growth at pH 6 or less. Broth cultures form aggregates in stationary phase, and static broth cultures form a thick, brittle pellicle near the surface. Colonies on agar medium are low convex, nonpigmented, smooth, shiny, and mostly regular in shape, raised with a wrinkled surface upon extended incubation for more than 72 h. Catalase‐ and oxidase‐positive. A narrow range of substrates are oxidized, mostly organic acids, for example, malate, succinate, fumarate, citrate, and oxaloacetate and also l‐glutamate and l‐proline; d‐galactonate and d‐gluconate are oxidized by some strains. Strict endophytes found in the leaf glands of the tropical yam Dioscorea sansibarensis.