Continuous fermentation open systems

In the early 1970s open fermentors and the continuous fermenting systems were found to be obsolete. The batch process was going to survive, and many new fermentor constmctions appeared. The cylindroconical fermentor seemed to be the preferred solution for both a single- and a combi-vessel fermentation system, ie, fermentation and 1 agering in the same vessel (Fig. 11). 

The idea of applying continuous culture to brewery fermentations was born in 1892 and the possibility of using high concentrations of yeast was mooted [67]. Equipment for continuous fermentation was patented in Paris in 1899 [68] and in Singapore in 1906 [63]. The latter process is of particular interest because it foreshadowed the cascade systems in which fermentation tanks are connected in series using an open system of fermentation partly fermented beer cascades from one tank to the next until fermentation is complete. 

In this paper, only the latter will be considered for the purpose of showing the influence of algebraic equations on open loop stability of process systems using illustrative examples of a continuous fermentation process model and a countercurrent heat exchanger. Special emphasis is put into the effect of different mechanisms, such as convection, transfer and reaction, occurring in lumped parameter process systems on local stability. 

In large-scale SSF, it is difficult to continuously monitor the pH change, and hence it is advised to use buffers in the medium. In open systems such as tray fermentation, aseptic operation is not possible and therefore pH and moisture play a crucial role in reducing the risk of contamination. 

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