Native catalase preparations isolated from Bacillus Sp were formulated with different additives for storage stabilization and better performance at high temperature and pH. The additives studied were: polyethylene glycol, glycerol, BSA, casein, glutaraldehyde, n-butylamine, ethylenediamine, 1.6-diaminohexane, BSA/glutaraldehyde and casein/glutaraldehyde. The glycerol and glutaraldehyde showed the best performance for long-term storage at 30degreesC and neutral pH. No stabilization additives were effective at pH 12, but below that pH the polyethylene glycol and glycerol appeared to be the most appropriate. Amines, polyethylene glycol and glycerol shifted the pH activity maximum of the native catalase toward more alkaline region, while glycerol were the only additive to improve the temperature profile of the enzyme.