INDUSTRIAL FERMENTATION PROCESS FOR BACILLUS USING TEMPERATURE SHIFT

Abstract

The present invention relates to the field of industrial fermentation. In particular, it relates to a method for cultivating a Bacillus host cell comprising the steps of (a) inoculating a fermentation medium with a Bacillus host cell comprising an expression construct for a gene encoding a protein of interest, (b) cultivating for a first cultivation phase the Bacillus host cell in said fermentation medium under conditions conducive for the growth of the Bacillus host cell and the expression of the protein of interest, wherein the cultivation of the Bacillus host cell comprises the addition of at least one feed solution and wherein the cultivation during the first cultivation phase is carried out at a first temperature, and (c) cultivating for a second cultivation phase the Bacillus host cell culture obtained in step (b) under conditions conducive for the growth of the Bacillus host cell and the expression of the protein of interest, wherein the cultivation comprises the addition of at least one feed solution and wherein the cultivation during the second cultivation phase is carried out at a second temperature, said second temperature being higher than the first temperature. The invention also provides for a Bacillus host cell culture obtainable by the said method.

Description

Claims

1. A method for cultivating a Bacillus host cell comprising the steps of (a) inoculating a fermentation medium with a Bacillus host cell comprising an expression construct for a gene encoding a protein of interest;(b) cultivating for a first cultivation phase the Bacillus host cell in said fermentation medium under conditions conducive for the growth of the Bacillus host cell and the expression of the protein of interest, wherein the cultivation of the Bacillus host cell comprises the addition of at least one feed solution and wherein the cultivation during the first cultivation phase is carried out at a first temperature; and(c) cultivating for a second cultivation phase the Bacillus host cell culture obtained in step (b) under conditions conducive for the growth of the Bacillus host cell and the expression of the protein of interest, wherein the cultivation comprises the addition of at least one feed solution and wherein the cultivation during the second cultivation phase is carried out at a second temperature, said second temperature being higher than the first temperature.

2. The method of claim 1, wherein said method further comprises obtaining the protein of interest from the Bacillus host cell culture obtained after step (c).

3. The method of claim 1, wherein the protein of interest is an enzyme.

4. The method of claim 1, wherein the expression construct comprises a nucleic acid sequence encoding the protein of interest operably linked to a promoter.

5. The method of claim 1, wherein said first cultivation phase is carried out for a time of at least about 3 h up to about 48 h.

6. The method of claim 1, wherein during the first cultivation phase the at least one feed solution provides a carbon source at increasing rates.

7. The method of claim 1, wherein said second cultivation phase is carried out for a time of at least about 3 h up to about 96 h.

8. The method of claim 1, wherein during the second cultivation phase the at least one feed solution provides a carbon source at a constant rate, at decreasing rates or at rates increasing less than the rates in step (b), wherein said constant rate or the starting rate of said decreasing rates or the staring rate of said rates increasing less than the rates in step (b) is below the maximum rate of the first cultivation phase.

9. The method of claim 1, wherein said first and said second temperature differ by about 3° C. to about 7°C.

10. The method of claim 1, wherein said first temperature is within the range of about 28° C. to about 32 °C.

11. The method of claim 1, wherein said second temperature is within the range of about 33° C. to about 37 °C.

12. The method of claim 1, wherein the yield of the protein of interest obtained after step c) is significantly increased compared to a control which has been obtained by carrying out the method wherein the said first and second temperature are identical.

13. The method of claim 12, wherein said yield is increased by at least 40%, at least 60%, at least 80%, at least 100%, at least 200%, at least 300% or at least 400%.

14. The method of claim 1, wherein said Bacillus is selected from the group consisting of: Bacillus licheniformis, Bacillus subtilis, Bacillus alkalophilus, Bacillus amyloliquefaciens, Bacillus brevis, Bacillus circulans, Bacillus clausii, Bacillus coagulans, Bacillus firmus, Bacillus jautus, Bacillus lentus, Bacillus megaterium, Bacillus pumilus, Bacillus stearothermophilus, Bacillus thuringiensis, and Bacillus velezensis.

15. The method of claim 1, wherein said expression construct for a gene encoding a protein of interest has been introduced into the Bacillus host cell by genetic modification.

16. The method of claim 1, wherein said at least one feed solution comprises at least one carbon source.

17. A Bacillus host cell culture obtainable by the method of claim 1.