AbstractFor systems such as jacketed vessels with significant dead time, cooling jacket dynamics and unpredictable but measurable load disturbances, advanced control concepts need to be used in order to achieve quality regulatory control. In the current work, optimal regulatory control theory has been applied to this problem. An optimal control algorithm is used to effectively control a batch fermentation reactor. The algorithm is easily implementable and very effective. It is capable of responding to both measurable and unmeasurable process disturbances.