Adaptive control of the Simultaneous Saccharification—Fermentation Process from Starch to Ethanol

Abstract

In this paper, a new adaptive control strategy for the fed-batch Simultaneous Saccharification—Fermentation Process from Starch to Ethanol (SSFSE) process is proposed in order to maintain the glucose concentration at a quasi-equilibrium state by feeding starch into the process only when the glucose production rate is lower than its consumption rate. By maintaining the equilibrium state for the glucose, it is possible to reach higher values for the ethanol production rate for a longer time; and therefore to increase the ethanol concentration along the process. As the adaptive controller requires online information about the glucose production and consumption rates, software sensors for them are developed. The difference between the estimated values for the consumption and production rates is considered as a control marker, which is used for determining the feeding profile of starch into the fermentor.