L-lysine-containing feed additives

Method for producing a granulated L-lysine-containing feed additive comprising

• a) fermenting L-lysine-producing microorganism in an aqueous medium under aerobic conditions to form a fermentation broth containing biomass and L-lysine, thereby completing the fermentation,
• b) determining, when desired, sulphate/L-lysine ratio (V) in the fermentation broth, where V=2×[SO42−]/[L-lysine],
• c) lowering pH by adding sulphuric acid to 4.9 to 5.2,
• d) setting the sulphate/L-lysine ratio to 0.85 to 1.2 by adding ammonium sulphate or sulphuric acid, if necessary, and
• e) granulating the mixture resulting from steps c) and d) to form a product, which granular product has an L-lysine content of 10 to 70% by weight (determined as lysine base, based on the total amount) and a pH of 3.5 to 5.1, measured as a suspension of 10% strength.