The present invention relates to enzymes and processes. In particular, there is described an isolated polypeptide comprising the amino acid sequence corresponding to Citrobacter freundii phytase or a homologue, a modified form, a functional equivalent or an effective fragment thereof. There is also described a host cell transformed or transfected with a nucleic acid encoding a bacterial phytase enzyme or a modified form as well as the use of such a phytase or modified form in food or animal feed.