Apparatus and method for monitoring cultures

1. A bubble excluder device adapted for use with, and attachment to, a probe for continuous measurement of the cell density of a culture in a liquid medium in an aerated fermenter, the bubble excluder device comprising an inlet and an outlet to allow flow of liquid through the device, the inlet having a conduit which, in use, is substantially vertical, the conduit comprising means for bubble exclusion which creates a serpentine flowpath within the conduit, the means for bubble exclusion serving to reduce or prevent ingress of bubbles from the liquid medium outside the device.

2. A bubble excluder device according to claim 1 , in combination with a probe for continuous measurement of the cell density of a culture, the probe comprising a sampling aperture exposed to the culture within a sleeve of the bubble excluder device to allow the probe to measure a characteristic of the culture.

3. A bubble excluder device/probe combination in accordance with claim 2 , wherein the probe measures the optical density of a culture medium.

4. A bubble excluder device/probe combination in accordance with claim 2 , further comprising a spectrophotometer.

5. A bubble excluder device/probe combination in accordance with claim 4 , wherein the spectrophotometer is an integral component of the probe.

6. A bubble excluder device/probe combination in accordance with claim 4 , wherein the spectrophotometer is optically linked to the rest of the probe by means of one or more optical fibres.

7. A bubble excluder device according to claim 1 , wherein the means for bubble exclusion is selected from the group consisting of: a plurality of baffles, a plurality of perforated plates, and a channel with a cross-section smaller than the diameter of the majority of bubbles present in the liquid medium.

8. A bubble excluder device in accordance with claim 1 , wherein the means for bubble exclusion comprises baffles provided at an angle to the axis of the conduit such that they slope in an upward direction.

9. A bubble excluder device, in accordance with claim 1 , wherein the means for bubble exclusion comprises a plurality of baffles, and wherein at least some of the baffles are arranged to overlap, so as to create a sinuous or serpentine fluid flow path between the baffles within the conduit.

10. A bubble excluder device/probe combination in accordance with claim 2 , wherein at least one fluid tight seal is provided between the bubble excluder device and an outer surface of the body of the probe.

11. A bubble excluder device/probe combination in accordance with claim 2 , wherein a fluid-tight seal is provided at each side of the sampling aperture.

12. A bubble excluder device in accordance with claim 1 , wherein the outlet is substantially aligned vertically with the conduit or inlet.

13. A bubble excluder device in accordance with claim 7 in combination with a probe for continuous measurement of the cell density of a culture, the probe comprising a sampling aperture exposed to the culture within a sleeve of the bubble excluder device to allow the probe to measure a characteristic of the culture.

14. A fermenter comprising a bubble excluder device in accordance with claim 1 .

15. A fermenter comprising a bubble excluder device/probe combination in accordance with claim 2 .

16. A method of monitoring the cell density of a culture during aerobic fermentation, the method comprising use of a bubble excluder device/probe combination in accordance with claim 2 .

17. A method of excluding bubbles from a probe in fluid flow contact with a liquid containing bubbles, the method comprising the step of attaching a bubble excluder device in accordance with claim 1 in operable relationship with the probe.

18. A method of making a bubble excluder device in accordance with claim 1 , wherein the method comprises the step of coupling a suitable inlet conduit and a suitable outlet to a sleeve.