Identifying a kLa-based scalable zone
Oxygen transfer is one of the most critical scale-up parameters for bioreactors, and it can be represented in the form of the volumetric mass transfer coefficient, kL
a. When oxygen transfer is the rate limiting factor for a cell culture process, maintaining constant kL
a can achieve scalable yield from small to large scale. For proper cell culture scale-up, it is important to select equipment of different sizes with similar kL
a capabilities that offer sufficient overlapping so that the small scale success can be replicated in large scale.
As an example, we determined the kL
a of differently-sized BioBLU®
c Single-Use Bioreactors (BioBLU 0.3c, 3c, and 50c) using the static gassing-out method  and identified a kL
a-based scalable zone between a kL
a of 1 and 6 h-1
(Figure 2). kL
a values in this range can be reached by all BioBLU®
c Single-Use Bioreactors tested and therefore replicated across scales.
Find more information on dissolved oxygen (DO) control in bioreactors