Phylogenetic analysis of 16s rRNA gene sequences revealed two branches , one including two isolates and closely related to the DeniTrifier species pseudomonas azotoformans (99.61% sequence identity with strain lam 1603t ) originally isolates from cereal grains , and another one including three isolates and more similar to pseudomonas libanensis (99.32% sequence identity with strain cip 10540t ) formerly isolated from Lebanese spring waters.