Innovative Cell Biomass Sensor for On-Line Fermentation Monitoring

BugLab, a US-based manufacturer of sensors for bioprocess monitoring, launches the proBE 3000, the first on-line sensor that can accurately measure cell biomass across the entire range of process conditions commonly encountered during microbial fermentations, in small (250 mL and lesser) to large (100 L and higher) scale vessels.

This product fulfills a long-standing need for combining a very wide linear range of sensitivity to cell biomass while discriminating against the effects of bubbles in on-line fermentation monitoring.

Martin Debreczeny, Co-Founder of BugLab

Traditional on-line Optical Density (OD) probes offer linear response over approximately one order of magnitude biomass range, while fermentations normally span over three orders of magnitude biomass range. Use of numerous OD probes has at times been used in an attempt to fill the ensuing measurement gaps, but this technique is expensive and difficult. Also, accurate on-line monitoring of cell biomass requires resistance to differing rates of agitation and gassing. This is a proven weakness of traditional on-line OD sensors, which are vulnerable to error when bubbles are present.

Therefore, off-line measurement has long been the chosen technique for biomass monitoring in fermentors; usually used to capture main decision points in the fermentation process, such as induction, inoculation, and harvesting. The problem of off-line sampling is, of course, that it is invasive and labor-intensive, so is normally conducted only at occasional intervals. Off-line sampling is also inclined to user error, particularly in the high biomass range where dilution of very viscous samples is required. The risk of contamination, sparsity of data, and the potential for cross-user error combine to render the off-line sampling non-ideal as a process monitoring technique.

The proBE3000 sensor removes the necessity to perform off-line cell biomass testing or use a number of on-line biomass probes:

• One proBE 3000 offers a linear range of cell biomass from less than 0.01 to more than 200 g/L dry cell weight (approximately equivalent to 0.03 to 600 OD at 600 nm) while maintaining strong resistance to alterations in process variables such as gassing and agitation rate
• Small diameter (3 or 4 mm) probe options offer access to even the smallest ports and fermentor sizes

BugLab has been delivering innovations in biomass monitoring in the bioprocess sector for more than 14 years.