Optimal control of a batch bioreactor for the production of a novel antifungal substance CF66I

Abstract

More than 80% of the plant diseases are caused by fungi. Usually, fungi not only destroy the plants, but also produce mycotoxins that are harmful to human health. At present, chemical fungicides are mainly used for the prevention of fungi-related plant diseases, however, research and development of biological prevention and controlling are of great importance. In this work, the effects of pH and temperature on cell growth and CF66I formation in batch culture of Burkholderia cepecia CF-66 were studied. The pH value has a marked effect on cell growth and production of CF66I. The lag phase was much longer when pH set lower (e.g.5.0) or higher (e.g.8.0). For earlier phase, optimal pH value was 6.0, because the lag phase can be shortened and the whole fermentation phase can also be shorten and then quickly goes into CF66I production phase. In the late phase, the higher pH is in favor of the production of CF66I. Different temperature have different effect on cell yield, specific growth rate, CF66I yield and specific synthesis rate. In the prophase of fermentation, it is better to set higher temperature to make the cell growth maximizing as soon as possible. However in mid-anaphase, lower temperature shortens the fermentation time, reduce heating energy and the cost. According about results, an optimal control strategy was constructed. © 2009 Academic Journals.