Knowledge of kLa (the volumetric mass-transfer coefficient that describes the efficiency with which oxygen can be delivered to a bioreactor for a given set of operating conditions) is not new. Here I provide information for those who are unfamiliar with the measurement method and/or issues that must be considered when making these measurements. Advances in this area now make it advisable to run kLa measurements routinely in many bioprocesses. The Importance of Measuring kLa Before examining the process theory and…