The Influence of Fluid Mixed State on Microorganisms: A Test Case with <i>Bacillus </i><i>subtilis</i>

Abstract

Flow pattern and mode have a far influence on the efficiency of biological treatment systems. In order to investigate the effects of different flow patterns on the growth of Bacillus subtilis, a self-developed fluid mixing device was designed to produce different liquid fluidization. It was found that the greater Re, the more conducive to the growth of bacteria, which evidenced by the logarithmic phase shorter and reached stationary phase bacteria concentration increased; when the Reynolds number is low, growth curve of Bacillus subtilis appeared Growth - stationary - growth and cell precipitation phenomenon, both phenomena gradually disappeared when Re increases. Besides, it can consume dissolved oxygen after inoculation with Bacillus subtilis, which keeping the dissolved oxygen in the medium at a lower level (0~1mg/L)