A composition for forming an aluminum film, comprising a complex represented by the following formula and a complex represented by the following formula, the molar ratio of the complex represented by the following formula and the complex represented by the following formula being 40:60 to 85:15:AlH3. The crude Mg2 is directly calcined and then treated with water to disintegrate the mass spontaneously to yield a slurry and dissolve away the soluble salts. hydrophila for use in the development of a vaccine, as well as the nucleic acid encoding said protein and vaccines comprising said protein or nucleic acid encoding said protein.