L-lysine-containing feed additives
The invention relates to relatively light and thermally stable granulated, fermentation-broth-based animal feed additives having a high content of L-lysine and to low-loss methods for their production from broths obtained by fermentation.
1 . Granulated fermentation-broth-based feed additive having
a) an L-lysine content of 10 to 70% by weight (calculated as base, based on the total weight), in particular 30 to 60% by weight,
b) a water content of 0.1 to 5% by weight (based on total weight), and
c) a sulphate/L-lysine ratio of 0.85 to 1.2, this ratio being calculated according to the formula 2×[SO 4 2− ]/[L-lysine]=ratio.
2 . Feed additive according to claim 1 having a pH of 3.5 to 5.1, measured in a 10% strength by weight aqueous suspension.
3 . Feed additive according to claim 1 , up to >97% of which has a mean particle size of 0.1 to 1.8 mm.
4 . Feed additive according to claim 1 , the surface of which is coated with an oil in an amount of 0.02 to 2% by weight, based on the total amount of the feed additive.
5 . Feed additive according to claim 1 , the colour values of which are in the following ranges: (measurement of diffuse reflection of the sample at an angle of 8°)
L*65-80 (black-white range)
a*4-8 (red-green range)
b*20-30 (yellow-blue range).
6 . Method for producing a granulated L-lysine-containing feed additive by fermentation of an L-lysine-producing microorganism in an aqueous medium under aerobic conditions, wherein, after completion of the fermentation
a) the sulphate/L-lysine ratio in the fermentation broth is optionally determined,
b) subsequently ammonium sulphate is optionally added and
c) the pH is lowered by adding sulphuric acid to 4.9 to 5.2, a sulphate/L-lysine ratio of 0.85 to 1.2 being set in the broth by addition of the sulphate containing compounds, and
d) the resultant mixture is optionally concentrated, granulated and a product is obtained which has an L-lysine content of 10 to 70% by weight (determined as lysine base, based on the total amount).
7 . Method according to claim 6 , in which the broth is concentrated by removal of water between steps c) and d).
8 . Method according to claim 6 , in which the sequence of the additions of ammonium sulphate and sulphuric acid is turned the other way round.
9 . Method according to claim 6 , in which, before the concentration, ammonium-, earthalkali- or an alkali metal hydrogensulphite or mixtures thereof are added in an amount of 0.01 to 0.5% by weight, based on fermentation broth.
10 . Method according to claim 6 , in which, after completion of the fermentation, 0 to 100% of the biomass formed during the fermentation is removed and steps a) to d) follow.
11 . Method according to claim 6 , in which the surface of the granules is coated with an oil in an amount of 0.02 to 2% by weight, based on the total amount of the feed additive.
12 . Method according to claim 6 , in which coryneform microorganisms are used.
13 . Method according to claim 6 , in which corynebacteria are used.