Modeling and Kinetic Parameter Estimation of the Enzymatic Hydrolysis Process of Lignocellulosic Materials for Glucose Production

The necessity to generate advances in the comprehension of modeling and simulation of enzymatic hydrolysis of lignocellulosic materials, based on experimentation, has attracted significant attention currently. This paper proposes a methodology for modeling and parameter estimation of the enzymatic hydrolysis process for sugarcane bagasse. The methodology is composed of three steps: experimental process, approach to the phenomenologically based semi-physical model, and parameter estimation. Experimentally, pretreated sugar cane bagasse was characterized, with 22.60, 13.39, and 23.71% for cellulose, hemicellulose, and lignin, respectively. The enzymatic hydrolysis of cellulose, cellobiose, and glucose concentrations was monitored using a commercial cellulase with an enzymatic activity of 96FPU/mL at 50 °C, pH 4.8, 130 rpm for 74 h. A model was proposed, which includes adsorption effects of the enzymatic complex, pH, temperature, transglycosylation, appearance of new cellulose, and product inhibition. Finally, a global mean percentage squared error cost function (% MSEGlobal) was used, adjusting the glucose, cellobiose, and cellulose variables from the estimation of 29 kinetic parameters. It was possible to obtain a % MSEGlobal of 6.33%, which is lower than the proposed acceptable error of 10%. Thus, the methodology for modeling and parameter estimation achieved good results in this first approximation from experimental development and the formulation of a more complex model.