Aim: In this study, the hydrodynamic behavior and mass transfer characteristics of
a cocurrent down flow contacting reactor (CDCR) were investigated for air-tap water and airfermentation
Observation: As gas and liquid flow rates increased, the values of kLa and gas hold ups
increased. The values of kLa measured in the air-fermentation broth system were all lower
than those in the air-tap water system, but the values of gas hold up were higher.
Result: Bacillus amyloliquefaciens bacterial was grown in a medium of 10 g L-1 glucose and
the specific growth rate, maximum dry cell concentration, and yield of biomass on glucose
were determined to be 0.310 h-1, 5.0 g dry cell L-1, 0.500 g dry cell g-1 glucose, respectively.
Conclusion: The values of kLa and qO2, increased at active growth phase and then decreased
with decreasing active cells.