L-AMINO ACID-CONTAINING FEEDSTUFF ADDITIVE

Abstract

Granulated animal feed additives having high bulk density were obtained by adding a surface-active substance to a fermentation broth containing amino acid before spray-drying, wherein low residual moisture levels were achieved at high spray rates and low granulator temperatures.

Claims

1-15. (canceled)

16. A method for preparing a feed additive containing an L-amino acid, comprising: a) providing a fermentation broth containing the L-amino acid and optionally one or more surface-active substances; b) determining the water content of the fermentation broth containing the L-amino acid and adjusting the content to 35 to 75% by weight if it is determined to be outside of that range; c) adjusting the amount of surface-active substance in the fermentation broth so that the total amount of surface-active substance present comprises 0.025 to 20% by weight; d) spray drying the fermentation broth of step c), to form a dried feed additive; wherein the amount of surface-active substance present prior to spray drying is sufficient to produce a dried feed additive with a particle density of at least 1.138 g/cm.sup.3.

17-18. (canceled)

19. The method of claim 16, wherein the amount of surface-active substance present prior to spray drying is sufficient to produce a dried feed additive with a particle density of 1.138 to 1.160 g/cm.sup.3.

20-22. (canceled)

23. The method of claim 16, wherein, prior to spray drying, the fermentation broth comprises a surface-active substance selected from the group consisting of: corn steep liquor, lipids, antifoaming agents, surfactants and mixtures thereof.

24. The method of claim 16, wherein, prior to spray drying, the fermentation broth comprises an antifoaming agent selected from the group consisting of: polysiloxanes, mono- and polyglycols, phospholipids and fatty acid glycerides.

25. The method of claim 16, wherein, prior to spray drying, the surface-active substance is present in the fermentation broth in an amount of 0.1 to 20% by weight.

26. The method of claim 16, wherein, prior to spray drying, the surface-active substance is present in the fermentation broth in an amount of 0.3 to 10% by weight.

27. (canceled)

28. The method of claim 16, wherein the L-amino acid is L-lysine, L-methionine, L-threonine, L-valine or L-tryptophan.

29. The method of claim 16, wherein the L-amino acid is L-lysine and, after completion of the fermentation and before the start of the drying, ammonium sulphate and/or sulphuric acid is added to the fermentation broth in order to establish a sulphate/L-amino acid ratio of 0.85 to 1.2.

30. The method of claim 16, wherein the fermentation broth used in spray drying comprises: a) a biomass content of 2 to 12% by weight; b) an L-amino acid content of 12 to 48% by weight; c) a solids content (including biomass) of 25 to 70% by weight; e) a percentage by weight ratio of sulphate to L-amino acid of 0.8 to 1.2; d) a surface-active substance content of 0.1 to 20% by weight.

31. The method of claim 30, wherein the fermentation broth used in spray drying comprises: a) a biomass content of 4 to 8% by weight; b) an L-amino acid content of 12 to 48% by weight; c) a solids content (including biomass) of 35 to 60% by weight; d) a surface-active substance content of 0.3 to 10% by weight.

32-35. (canceled)

36. A method for preparing a feed additive, comprising the following steps: a) obtaining a fermentation broth by: i) fermenting an L-amino acid-producing microorganism in an aqueous culture medium to produce a fermentation broth; ii) after the fermenting step i) is complete: adding surface-active substance to the fermentation broth to a final concentration of 0.025 to 20% by weight; and b) drying the fermentation broth obtained in step (a) in order to convert it into said feed additive; wherein the concentrations of biomass and surface-active substance in the fermentation broth are such that the feed additive of step b) is a particulate composition with a particle density of at least 1.138 g/cm.sup.3.

37. The method of claim 36, wherein the amount of surface-active substance present prior to drying is sufficient to produce a dried feed additive with a particle density of 1.138 to 1.160 g/cm.sup.3.

38. The method of claim 36, wherein, prior to drying, the fermentation broth comprises a surface-active substance selected from the group consisting of: corn steep liquor, lipids, antifoaming agents, surfactants and mixtures thereof.

39. The method of claim 36, wherein, prior to drying, the fermentation broth comprises an antifoaming agent selected from the group consisting of: polysiloxanes, mono- and polyglycols, phospholipids and fatty acid glycerides.

40. The method of claim 36, wherein, prior to adding the surface-active substance in step a)ii), the water content of the fermentation broth is adjusted to a value of 35 to 50% by weight.

41. The method of claim 36, wherein, prior to drying, the surface-active substance is present in the fermentation broth in an amount of 0.3 to 10% by weight.

42. The method of claim 36, wherein the L-amino acid is L-lysine, L-methionine, L-threonine, L-valine or L-tryptophan.

43. The method of claim 36, wherein the L-amino acid is L-lysine and, after completion of the fermentation and before the start of the drying, ammonium sulphate and/or sulphuric acid is added to the fermentation broth in order to establish a sulphate/L-amino acid ratio of 0.85 to 1.2.

44. The method of claim 36, wherein the fermentation broth used in drying comprises: a) a biomass content of 2 to 12% by weight; b) an L-amino acid content of 12 to 48% by weight; c) a solids content (including biomass) of 25 to 70% by weight; e) a percentage by weight ratio of sulphate to L-amino acid of 0.8 to 1.2; d) a surface-active substance content of 0.1 to 20% by weight.

45. The method of claim 44, wherein the fermentation broth used in drying comprises: a) a biomass content of 4 to 8% by weight; b) an L-amino acid content of 12 to 48% by weight; c) a solids content (including biomass) of 35 to 60% by weight; d) a surface-active substance content of 0.3 to 10% by weight.

Description

FIGURES

[0138] A cross section of granulate embedded in synthetic resin is shown in FIGS. 1a and 1b, which was obtained from the fermentation broth without addition of a surface-active substance (FIG. 1a) compared to a cross section of a granulate to which corn steep liquor had been added before carrying out the spray granulation (FIG. 1b). Distinct cavities are visible in FIG. 1a, while the granulate in FIG. 1b has a more compact structure without visible cavities.

WORKING EXAMPLES

Laboratory Experiments

[0139] The laboratory experiments were conducted in a laboratory granulator. The laboratory granulator operates with a fluidized bed. The fermentation broth containing lysine is sprayed into the reactor from above. The fluidized bed supply air may be adjusted in amount and temperature by controllable blower speeds and electrical heating. The air flow is adjusted such that a well-mixed fluidized bed is achieved. The spray nozzle is a pneumatic dual component nozzle. The atomizing air pressure was adjusted to 0.5 bar in each experiment. The broth was preheated to 60° C. and conveyed by means of a peristaltic pump with variable speed settings. The fermentation broth containing lysine was evaporated to a water content of ca. 40% by weight before the spray-drying process and the surface-active substance was subsequently added.

[0140] The primary fluidized bed was generated, in which seeds were charged, which were removed from the production and were sieved to a particle size of 200 to 710 μm. The particle density was selected as target parameter, since a good correlation was established between production and laboratory and a direct dependency of the particle size on the bulk density could be detected.

[0141] The bulk density was determined as follows: An empty measuring cylinder (250 ml volume) was placed on a balance, filled with the granular product and the weight per unit volume was then determined.

[0142] To determine the particle density, the void spaces in the measuring cylinder were filled with methanol. The void volumes could thus be determined by the increase in weight and the known density of methanol (0.7918 g/ml). The difference between total volume and the volume of the methanol gives the particle volume. The particle density is then obtained, by basing the weight of the particle previously determined not on the total volume of the measuring cylinder but on the particle volume determined.

[0143] Alternatively, the particle density can also be determined using a pycnometer.

Example 1: Influence of an Antifoaming Agent on the Particle Density

[0144] Fermentation broth containing lysine sulphate was evaporated to a water content of ca. 40% by weight. The fermentation broth provided in this manner already comprised 0.13% by weight of antifoaming agent CLEROL FBA 975-US. The fermentation broth was then treated with various amounts of the fatty acid alkylpolyglycol ester (CLEROL FBA 975-US) and was then converted into a granulate using a laboratory granulator. The concentrated fermentation broth was subjected to spray granulation without subsequent addition of the fatty acid alkylpolyglycol ester as comparative example. The influence of the subsequent addition of the fatty acid alkylpolyglycol ester on the particle density can be seen in the following table.

TABLE-US-00001 TABLE 1 Influence of an antifoaming agent on the particle density of granulate containing lysine. Particle density [g/cm.sup.3] Fermentation broth 1.133 +0.09% by weight antifoaming agent 1.137 +0.13% by weight antifoaming agent 1.155 +0.26% by weight antifoaming agent 1.145

[0145] It can be seen that the subsequent addition of the antifoaming agent before carrying out the granulation leads to a distinct increase in the particle density of the resulting granulate.

Example 2: Influence of Lipids on the Particle Density

[0146] Fermentation broth containing lysine sulphate was evaporated to a water content of ca. 40% by weight. The fermentation broth provided in this manner already comprised 0.13% by weight of antifoaming agent CLEROL FBA 975-US. The fermentation broth was then treated with various amounts of lipid-containing components. The lipid-containing components used were lecithin (Aquagran CP 100) and also corn steep liquor (“CSL”), which contains lecithin. The fermentation broth was subsequently processed to a granulate in the spray granulation process. The concentrated fermentation broth was used in the spray granulation without subsequent addition of lipid-containing components as comparative example. The results are shown in the following table.

TABLE-US-00002 TABLE 2 Influence of lipids on the particle density of granulate containing lysine and the spray rate achievable in the granulation process. Particle density Spray rate [g/cm.sup.3] [g/min] Fermentation broth 1.132 9.3 +8.23% by weight CSL 1.143 10.8 +0.025% by weight Aquagran CP 1000 1.142 10.9 +0.05% by weight Aquagran CP 1000 1.147 11.4 +0.25% by weight Aquagran CP 1000 1.149 10.7 +0.5% by weight Aquagran CP 1000 1.146 11.2

[0147] It can be seen that the subsequent addition of lecithin and corn steep liquor before carrying out the granulation also leads to a distinct increase in the particle density of the resulting granulate.

[0148] In addition to the increased particle density, it was observed that the addition of the surface-active components led to an increased spray rate being achievable at the same energy input in the granulation apparatus and the same granulation air outlet conditions (right-hand column of the table). This means that a more energy-efficient drying process is possible.

Example 3: Influence of Surface-Active Substances on the Granulation Process on a Production Scale

[0149] On account of the laboratory experiments, corn steep liquor was now used as additive in the production scale preparation of lysine. The comparative experiments were conducted without addition of corn steep liquor.

[0150] To conduct the experiments, the fermentation medium was first concentrated after completion of the fermentation to a water content of ca. 40% by weight. Corn steep liquor was then added in an amount of ca. 8% by weight. Corn steep liquor was omitted in the corresponding comparative experiment.

[0151] Subsequently, spray granulation was conducted in each case in a granulator. The resulting bulk densities were subsequently determined. The results are shown in the following table.

TABLE-US-00003 TABLE 3 Influence of corn steep liquor on the bulk density of granulate containing lysine. Bulk density [kg/m.sup.3] Fermentation medium 620.2 +8% by weight corn steep liquor 665.4

[0152] As can be seen, the bulk density is significantly increased by addition of corn steep liquor prior to the spray granulation.

[0153] As in the laboratory scale experiments, the spray rates could be increased also on a production scale following addition of corn steep liquor without increasing the residual moisture content. This led to significantly lower outlet temperatures in the granulator air.