The paper is dedicated to the analysis of the scale-up of an aerobic stirred bioreactor from 4 L working volume to 40 L using the mixing time criterion, taking into account its required conditions and effects. Therefore, if the selected operating parameters allow obtaining similar values of mixing time in the larger bioreactor as in the reference one, it
is possible to maintain also the specific power consumption by scaling-up. However, the shear forces in the larger bioreactor are amplified with 23 – 35 %, the most important increase being recorded for high viscous broths
