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DOWNLOADPaul Sauer, Associate Scientist of Protein Design Lab's Cell Culture Development Group, had two compelling reasons for specifying mass flow controllers for his work: The first was the need to acquire an array of data that would allow them to more effectively control 
fermentation processes; The second was the need to minimize the formation of foam in the bioreactor's headspace. To minimize foam, they needed to reduce the net volume of air and oxygen gases that were being bubbled into the culture medium. The rotameter that Protein Design Labs had been using was not adequate for measuring the low flow rates needed to prevent excessive foaming. According to the flow tubes, they had been flowing at about 60 ml per minute.
SIERRA'S SOLUTION
After installing the Sierra SideTrak® 840, they realized that we had been flowing at much more than 60 ml per minute, perhaps up to three times as much. At a 60 ml setting, the MFCs reduced the foam significantly.
Protein Design Labs now uses a B. Braun Biostat® MDC A54 automated fermenter to scale up culture strains to bulk production levels. The six-fermenter Biostat system, configured specifically for Protein Design Labs, includes a digital control unit (DCU) and 12 Sierra mass flow controllers. Working with the B. Braun Biostat fermenter, they have found that Sierra mass flow controllers permit them to flow a precise low volume of air and reduce foam formation. The Braun system with the mass flow controllers also offers a considerably more refined tool that provides more information.
By monitoring and metering gas mass flow ratios precisely, the mass flow controllers also provide an elegant and relatively straightforward way of measuring the oxygen uptake rate using the static method that was not possible with solenoid valves.
Here's what makes Sierra's SideTrak 840 an ideal choice:- One of the world's most dependable analog mass flow controllers
- Precise primary standard calibration to measure any clean, dry gas with
low pressure drop - Highly accurate for oxygen, mixtures, toxics, corrosives and combustibles
- Widely used in process control, leak detection, gas distribution and scientific research