Characterization of power input and its impact on mass transfer in a rocking disposable bioreactor.

• Power input to the liquid was measured using electrical current and voltage. • Rocking action results in a periodic power curve, best characterized by peak power. • Mass transfer coefficient (k L a) is related to peak power input via a power law model. • Rocking bioreactor power inputs of up to 800 W/m3 are achievable. The impact of specific power input on gas-liquid mass transfer and mixing has not been extensively reported for rocking disposable bioreactors. An electrical method was applied for measuring the specific power input into a disposable rocking (Wave) bioreactor at benchtop scales. The peak power input was shown to be suitable for characterizing the impact of operational parameters including rocking frequency, rocking angle and liquid volume. The average power inputs ranged from 66.5 W/m3 to 680.1 W/m3 which were comparable to those for stirred tank and orbitally-shaken disposable bioreactors. The gas-liquid oxygen mass transfer coefficient was shown to correlate with the peak power input in a power law model, confirming that the mass transfer capacity rapidly increased with power input, especially at 600 W/m3 and greater. The correlation between mixing time and power input indicated that power input at higher than 400 W/m3 was sufficient to induce relatively rapid mixing. [ABSTRACT FROM AUTHOR]