KINETIC STUDY OF THE BATCH ENZYMATIC HYDROLYSIS OF SODA-ETHANOL PULPS FROM PINE SAWDUST USING THE MICHAELIS-MENTEN MODEL

MENDIETA, C. M.; KRUYENISKI, J.; FELISSIA, F. E.; AREA, M. C.

Congreso; XXV TECNICELPA - Conferência Internacional da Floresta, Pasta e Papel XI CIADICYP; 2021

This work evaluates the maximum glucose concentration of the batch enzymatic hydrolysis of soda-ethanol pulps from pine sawdust and determines the fundamental parameters of the enzymatic kinetics following the pseudo-homogeneous Michaelis-Menten kinetic model. Three highly delignified pine sawdust soda-ethanol pulps with different initial chemical composition, glucan range 67-80%, and lignin range 10 to 3.7%, respectively, were evaluated. The pulps were enzymatically saccharified using Novozyme Cellic Ctec2 cellulolytic enzymes, in a buffer solution (1% hydrolyzable cellulose, 0.05 M sodium citrate), at pH 5. The suspensions were treated using 30 FPU/g of the substrate at 130 rpm, maintaining the temperature at 50°C. Samples were taken every 8 hours until 48 hours. The obtained kinetic parameters were the apparent constant (k= 4.39 h-1), which represents the link frequency between cellulose and cellulase, the Michaelis-Menten apparent constant (KM=76.06 gL-1) that indicates the cellulose/cellulase affinity, and the apparent constant of inhibition between cellulose-glucose and cellulase (KI=10.59 gL-1). The rate of glucose production was determined by the selected parameters. The maximum glucose value reached during the reaction (T∞) was 9.87 gL-1. Glucose values calculated by the model fit close to the glucose values obtained in the experimental saccharification process, demonstrating the applicability of the kinetic model.