Amphibacillus xylanus is a gram-positive-spore forming bacterium with cells 0.3 μm to 0.5 μm in diameter and 0.9 μm to 1.9 μm in length. A. xylanus is a facultative anaerobic organism which can grow in several different environments. Its success in a multitude of environments stems from multiple metabolic pathways, each with high ATP yields. It is flagellated and motile. It grows best at pH 8.0-10.0 but not at pH 7.0. It is catalase and oxidase negative. This helps to explain better the unique method of metabolism on which the organism relies.