APPROACH
A new in-situ probe was developed to capture and measure bubbles passing through the notch of a stainless steel probe. The system utilized a digital high speed, high resolution enclosed modular optical system. The system was compatible with standard ingold ports utilized on fermenters and is fully autoclavable.

APPARATUS
An EnviroCam B Series utilizing backlighting captured still frames and/or video of bubbles passing through the notch of the shroud. A LED light source was integral with the shroud. The bubbles were analyzed using customized version of National Instruments LabView™ the most widely accepted platform for process control. Using this system, bubbles sizes where measured as a function of various operating parameters (e.g., agitation rate, aeration rate) and as a function of media properties (e.g., viscosity, antifoam, and microbial/animal cell broths) to demonstrate system performance.

CONCLUSIONS
For selected conditions, sauter mean bubble size changes qualitatively compared favorably with published relationships. The information provided by the EnviroCam B confirmed bubble formulas of presently used theories and gave new insights regarding bubble formation and bubble behavior in a fermenter. This information impacted the design of fermenter/bioreactor spargers.

BENEFITS
Data provided by the EnviroCam B system allowed the fermenter to operate at optimized efficiency thereby increasing process yields, while at the same time conserving power consumption and reducing costs.