Response of Bakers' Yeast to Transient Environmental Conditions Relevant to Large-Scale Fermentation Processes

摘要

The performance of large-scale fermentation processes is often characterized by insufficient liquid mixing, mass transfer and heat transfer. Micro-organisms circulating through a large fermentor are exposed to a continually changing environment. This will often result in a loss of productivity. The scale-up, optimization and design of bioreactors is still often based on experience, rules of thumb and trial-and-error. Therefore, a more structured approach to bioreactor scale-up is needed. The scale-down procedure seems to be an adequate tool in this respect. The thesis presents the results of scale-down investigations which were aimed at a study of the influence of continually changing environmental conditions on a microbial culture. The fed-batch production of bakers' yeast was chosen as the model system for the experiments. The analysis of large-scale reactors was based on a bubble column fermentor.