Enzymatic hydrolysis and fermentation strategies for the biorefining of pine sawdust

• Published in: Bioresources Vol. 16; no. 4; pp. 7474 - 7491
• Main Authors: Mendieta, Carolina Mónica, Felissia, Fernando Esteban, Arismendy, Ana María, Kruyeniski, Julia, Area, María Cristina
• Format: Journal Article
• Language: English
• Published: Raleigh North Carolina State University 01-11-2021
• Subjects: Alternative energy sources; Biofuels; Biomass; Carbohydrates; Cellulase; Cellulolytic enzymes; Cellulose; Chemical composition; Enzyme kinetics; Ethanol; Experiments; Fermentation; Glucose; Hydrolysis; Lignin; Lignocellulose; Pulp; Renewable resources; Saccharification; Sawdust; Yeast; Yeasts; Argentina
• ISSN: 1930-2126; 1930-2126
• DOI: 10.15376/biores.16.4.7474-7491

This work aims to evaluate second-generation bioethanol production from the soda-ethanol pulp of pine sawdust via two strategies: separate hydrolysis and fermentation and simultaneous saccharification and fermentation. A kinetics study of the enzymatic hydrolysis of separate hydrolysis and fermentation was included as a design tool. Three soda-ethanol pulps (with different chemical compositions), Cellic® Ctec2 cellulolytic enzymes, and Saccharomyces cerevisiae IMR 1181 (SC 1181) yeast were employed. The obtained kinetic parameters were as follows: an apparent constant (k) of 11.4 h-1, which represents the link frequency between cellulose and cellulase; a Michaelis-Menten apparent constant (KM) of 23.5 gL-1, that indicates the cellulose/cellulase affinity; and the apparent constant of inhibition between cellulose-glucose and cellulase (KI), which was 2.9 gL-1, 3.1 gL-1, and 6.6 gL-1 for pulps 1, 2, and 3, respectively. The kinetic model was applicable, since the calculated glucose values fit the experimental values. High bioethanol yields were obtained for pulp 3 in the separate hydrolysis and fermentation and simultaneous saccharification and fermentation processes (89.3% and 100% after 13 h and 72 h, respectively).