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.
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.
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.
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.
FERMENTOR BUBBLE ANALYSIS
Determine the feasibility of developing an in-process measurement instrument to observe bubble size, volume and distribution in a closed pharmaceutical bioreactor/fermenter. The goal was to facilitate scale-up from research and development through preproduction to production. The system would also be used to provide characterization of a fermenter.
Merck Research Laboratories, Rahway, NJ