aquaspirillum bengal aquaspirillum bengal aquaspirillum bengal is a gram negative bacterium in the genus aquaspirillum. aquaspirillum bengal scientific classification domain: bacteria phylum: pseudomonadota class: betaproteobacteria order: neisseriales family: neisseriaceae genus: aquaspirillum species: a. bengal binomial name aquaspirillum bengalkumar et al. 1974 description the species is helical in shape and moves in water through flagella. the cell is 0.9 to 1.2 μm in diameter and 5.2 to 22.0 μm in length.