Power consumption and mixing in a miniaturised bioreactor

Abstract

Microbial fermentation plays an important role in digesting renewable biomass, in particular lignocellulose to generate new sources of chemical raw material and energy. The increasing number of genetic and process permutations during screening for process optimizations drives a strong demand for obtaining accurate biological and process data in short time frames and at low cost. A novel miniaturised bioreactor with a working volume of 7mL was fabricated to meet the requirements of fermentation process development. The engineering parameters including power consumption and mixing time were characterised and compared with those in a 7 L bioreactor with two standard Rushton impellers. Computational results in the 7L bioreactor were in good agreement with the literature and his approach was applied to this miniaturised bioreactor. Power number for the impellers used in the miniaturised reactor was found to vary with the detailed impeller geometrical characteristics, including the blade width, length and thickness. Mixing time in this miniaturised bioreactor was calculated to be around 0.2 s, shorter than the time required for metabolic regulations for some cells. This miniaturised bioreactor could dramatically change the fermentation process development.