Optimal control strategy for fed-batch enzymatic hydrolysis of lignocellulosic biomass based on epidemic modeling

ABSTRACT A mathematical optimal control strategy for feeding operation was developed for fed‐batch enzymatic hydrolysis of dilute acid pretreated lignocellulosic biomass based on a modified epidemic model. Cellulose conversion was maximized and glucose concentration achieved highest possible value over a fixed hydrolysis time. Boundaries of feeding rate and lignin content were set for feasible controls. Using the optimal control feeding strategy, glucose concentration and accumulated cellulose conversion reached up to 77.31 g/L and 72.08% in 100 h, which are 108.76% and 37.50% higher than in batch hydrolysis with same amount of enzyme consumption. Solids content in feeding source has a significant interference on system mass transfer. Optimal control is a useful tool for guiding operations in fed‐batch and continuous processes as it enables process optimization through clear objective functions and feasible controls. Biotechnol. Bioeng. 2015;112: 1376–1382. © 2015 Wiley Periodicals, Inc. Enzymatic hydrolysis of complex substrate has been studied with a new perspective. The process of substrate getting adsorbed and digested by enzyme was simulated as susceptible getting infected by virus and becoming removed. Optimal control theory was applied to optimize substrate feeding with the objective functions of maximizing cellulose conversion during the reaction and glucose concentration at the end of the reaction.