Oxygen transfer rates in culture vessels from Fernbachs flasks to 96-well microtiter plates at various fill volumes, rpm, shaker throws, microtiter plate cover hole diameters, and viscosities.

Perhaps the most commonly compromised process parameter in high throughput (HTP) microbial screens is oxygen transfer.  Poor translation of microtiter plate (MTP) results to larger scales may occur when the increased product formation observed under oxygen limiting conditions of MTPs are not seen under the oxygen-sufficient conditions of stirred bioreactors.  As part of efforts to improve our screens, we conducted studies to determine relative oxygen transfer rates (OTRs) in 11 vessel formats from 2.8 L Fernbach flasks to 96-well MTPs at various fill volumes, rpm, shaker throws, and MTP cover hole diameters.  In addition, we determined OTRs in liquids that had been thickened to viscosities commonly found in cultures of actinomycetes.  The outcome of these results on the design of our screening methods to guard against oxygen-limited strain evaluations will be discussed.