Cell culture and mixing vessel

1. A cell culture and mixing vessel for containing a liquid, comprising

a chamber having a lower chamber portion and an upper chamber portion wider than the lower chamber portion,

a gas inlet for supplying gas to the lower chamber portion, the height of liquid being selectable such that when in use, liquid in the upper chamber portion circulates within the upper chamber portion as a result of the introduced gas and G =(H ×A)/V is greater than 1.5, wherein A is the surface area of liquid in the vessel, H is the rise height of the gas and V is the volume of liquid,

wherein the chamber has a front wall and a back wall,

wherein when the back wall is vertically orientated, the front wall is inclined at an angle of incline, and

wherein the angle of incline has an initial value which with increasing height is immediately followed by a reduction in the value of the angle of incline.

2. A vessel according to claim 1 , wherein the reduction in the value of the angle of incline is in turn followed by an increase in the value of the angle of incline of the front wall.

3. A vessel according to claim 1 , which further comprises an abutment for redirecting rising gas inclined with respect to the direction of rising gas, such that when in use, rising gas in the form of bubbles, initially rises substantially vertically in the liquid and is redirected in a substantially horizontal direction within the chamber by the abutment.

4. A vessel according to claim 3 , wherein the chamber comprises

a back wall, at least a part of which is vertical or substantially vertical, and

a front wall.

5. A vessel according to claim 4 , wherein the abutment is inclined relative to the vertical or substantially vertical part of the back wall.

6. A vessel according to claim 5 , wherein the abutment is a non-vertical part of the back wall.

7. A vessel according to claim 1 , wherein there is no physical barrier between any rising regions of liquid and any descending regions of liquid.

8. A vessel according to claim 4 , wherein the gas inlet extends across substantially the whole length of the back wall.

9. A vessel according to claim 4 , wherein at least part of the back wall is planar, and wherein the at least part of the back wall extending upwards from a level of the front wall at which the front wall has the initial value of angle of incline to a level at which the reduction in the angle of incline has occurred.

10. A vessel according to claim 1 , wherein the widening of the vessel with respect to height occurs asymmetrically.

11. A vessel according to claim 1 , wherein the lower chamber portion is tapered, becoming wider with increasing height.

12. A vessel according to claim 1 , wherein at least a lower part of the upper chamber portion is tapered becoming wider with increasing height.

13. A vessel according to claim 1 , which is made out of flexible plastics material.

14. A vessel according to claim 1 , wherein the gas inlet comprises one or more tubes with a gas permeable wall.

15. A vessel according to claim 1 , wherein the gas inlet has a plurality of exit holes, wherein each exit hole is of a size in a range of from 0.1 microns to 1 mm.

16. A vessel according to claim 1 , further comprising a means for regulating the temperature of the liquid in the vessel.

17. A vessel according to claim 1 , further comprising a means for providing a controllable pressure in gas above the liquid.

18. A vessel according to claim 1 , arranged such that when in use, liquid in the upper chamber portion circulates within the upper chamber portion as a result of the introduced gas.

19. A mixing apparatus comprising a vessel according to claim 1 .

20. A mixing apparatus according to claim 19 , further comprising a separate controller device.

21. A vessel according to claim 1 , wherein the reduction of the angle of incline is by at least 20° .

22. A vessel according to claim 15 , in which each exit hole is of a size in a range of from 1 to 100 microns.

23. A method of performing a cell culture fermentation in a vessel, the vessel containing a liquid medium and cells to be cultured, and having a tapered lower chamber portion and a tapered upper chamber portion wider than the lower chamber portion, the method comprising the steps of

filling the vessel with a volume V of liquid medium, thereby to obtain a surface area A of liquid in the vessel, and

supplying a gas to the gas inlet of the vessel thereby to cause the gas to be admitted to the lower chamber portion to rise through a height H to the surface of the liquid and to cause liquid in the upper chamber portion to circulate within the upper chamber portion as a result of the introduced gas, wherein G =(H ×A)/V is greater than 1.5, A being the surface area of liquid in the vessel, H the rise height of the gas in the liquid and V the volume of the liquid in the vessel.

24. A cell culture and mixing vessel, comprising

a chamber having a tapered lower chamber portion and a tapered upper chamber portion wider than the lower chamber portion;

a gas inlet for supplying gas to liquid in the lower chamber portion; and

an abutment with a structure sufficient to redirect rising gas in the form of bubbles, initially travelling substantially vertically, substantially horizontally within the chamber, wherein G =(H ×A)/V is greater than 1.5, where A is the surface area of liquid in the vessel, H is the rise height of the gas and V is the volume of liquid, wherein the angle of the taper of the lower chamber portion is in the range of 5° to 40° , the angle of the taper of at least a lower part of the upper chamber portion is in the range of 25° to 80° , and wherein the lower part of the upper chamber portion has a smaller angle of inclination relative to the horizontal than the lower chamber portion.