Scale-up from shaker flask to stirred-tank fermenter based on mass transfer coefficient of oxygen, kLa

Abstract

This study is carried out to investigate gas-liquid mass transfer process in a shaker flask and a 2 L bioreactor. Deionized water was used as based medium whereas shaker flask was scaled up to a 2 L bioreactor scale by using method of constant oxygen mass transfer coefficient, kLa. kLa values were derived by fitting the mass transfer equation to the data of dissolved oxygen percentage (DO) versus time. Screening of Design of Experiment (DOE) was performed and analysis of variance (ANOVA) was run in order to determine the significance of factors that affecting the kLa value. Based on ANOVA, stirring speed and aeration rate were significant factors for both shaker flask and 2 L bioreactor scales but temperature was not. A regression equation was generated for both shaker flask and 2 L bioreactor scales. For shaker flask, 666 rpm of stirring speed with 1 LPM aeration rate was required to obtain 0.5 min-1 of kLa value. Meanwhile, for 2 L bioreactor, 1 LPM of aeration rate without stirring was required to obtain same value of kLa. At the end of this study, shaker flask was successfully scaled up to 2 L bioreactor scale with constant kLa and the significance of factors was studied.