Optimization of biotechnological processes. The acetic acid fermentation. Part III: Dynamic optimization

Abstract

Wine vinegar is obtained in a biotechnological process one of the crucial steps in which is the biological oxidation of the starting wine. Such a step is usually performed in a semi-continuous operation mode where a preset fraction of the culture medium is unloaded from the fermenter as product and the remainder left in it as inoculum to facilitate expeditious fermentation of the wine subsequently added to replenish the amount withdrawn. The overall performance of the fermenter can vary markedly depending on the particular operating conditions, and so can the quality of the product and the economy of the process as a result. Identifying the most suitable operating conditions therefore poses a typical optimization problem named as dynamic optimization or open-loop optimal control, which is solved by determining the time profiles for the control variables of the system in order to optimize a given cost function. Such a function represents the goal to be achieved as regards the specific needs of the problem. In Part III of this series the previously proposed model in Parts I and II has been used for addressing the dynamic optimization of the acetic fermentation process in terms of various objective functions, with special emphasis on productivity.