Use of acid-stable subtilisin proteases in animal feed
Acid-stable proteases of the subtilisin family, their use in animal feed, feed-additives and feed compositions containing such proteases, and methods for the treatment of vegetable proteins using such proteases.
1. An animal feed additive comprising (a) at least one purified acid-stable subtilisin and (b) one or more fat soluble vitamins and/or water soluble vitamins, and (c) one or more trace minerals, wherein the acid stability of the subtilisin means that the activity of the pure subtilisin, in a dilution corresponding to A 280 =1.0, is at least 40% of the reference activity of the subtilisin, wherein the activity of the subtilisin is measured after two hours incubation at a temperature of 37° C. in a buffer of 100 mM succinic acid, 100 mM HEPES, 100 mM CHES, 100 mM CABS, 1 mM CaCl 2 , 150 M KCl, and 0.01% Triton X-100 (pH 3.5); and wherein the reference activity is measured after two hours incubation at a temperature of 5° C. in the same buffer but adjusted to pH 9.0, wherein the activity and reference activity are measured after these incubations, at 25° C. in Suc-AAPF-pNA (pH 9.0).
2. The animal feed additive of claim 1 , wherein the activity of the pure subtilisin is at least 45% of the reference activity of the subtilisin.
3. The animal feed additive of claim 2 , wherein the activity of the subtilisin is at least 50% of the reference activity.
4. The animal feed additive of claim 3 , wherein the activity of the subtilisin is at least 60% of the reference activity.
5. The animal feed additive of claim 1 , wherein the subtilisin has a pH optimum in the range of 6.0-11.0.
6. The animal feed additive of claim 1 , wherein the subtilisin is a Bacillus sp., NCIMB 40484 subtilisin.
7. The animal feed additive of claim 1 , wherein the subtilisin is a Bacillus alcalophilus NCIMB 10438 subtilisin.
8. The animal feed additive of claim 1 , wherein the subtiuisin is a Fusarium oxysporum IFO 4471 subtilisin.
9. The animal feed additive of claim 1 , wherein the subtilisin is a Paecilomyces lilacinus CBS 102449 subtilisin.
10. The animal feed additive of claim 1 , wherein the subtilisin is an Acremonium chrysogenum ATCC 48272 subtilisin.
11. The animal feed additive of claim 1 , wherein the subtilisin is an Acremonium kiliense ATCC 20338 subtilisin.
12. The animal feed additive of claim 1 , wherein the amount of the purified subtilisin corresponds to 0.01-200 mg subtilisin protein per kg feed.
13. An animal feed additive of claim 1 , for addition to an animal feed having a crude protein content of 50-800 g/kg.
14. The animal feed additive of claim 1 , which further comprises at least one enzyme selected from the group consisting of phytase, xylanase, galactanase, and beta-glucanase.
15. A method for the improving the nutritional value of a vegetable protein or protein source, comprising adding an animal feed additive of claim 1 to the vegetable protein or protein source.
16. The method of claim 15 , wherein the vegetable protein comprises soybean.
17. The method of claim 15 , wherein the subtilisin is a Bacillus sp., NCIMB 40484 subtilisin.
18. The method of claim 15 , wherein the subtilisin is a Bacillus alcalophilus , NCIMB 10438 subtilisin.
19. The method of claim 15 , wherein the subtilisin is a Fusarium oxysporum , IFO 4471 subtilisin.
20. The method of claim 15 , wherein the subtilisin is a Paecilomyces lilacinus , CBS 102449 subtilisin.
21. The method of claim 15 , wherein the subtilisin is an Acremonium chrysogenum , ATCC 48272 subtilisin.
22. The method of claim 15 , wherein the subtilisin is an Acremonium kiliense , ATCC 20338 subtilisin.