High Solid and Low Cellulase Enzymatic Hydrolysis of Cardoon Stems Pretreated by Acidified Γ-Valerolactone/Water Solution

• Main Authors: Cavalaglio, G. (Author), Coccia, V. (Author), Fabbrizi, G. (Author), Gelosia, M. (Author), Giannoni, T. (Author), Iodice, P. (Author), Lorenzi, L. (Author), Nicolini, A. (Author)
• Format: Article
• Language: English
• Published: MDPI 2022
• Subjects: Cellulose; cellulose enrichment; Cellulose enrichment; Cynara cardunculus; Delignification; Enzymatic hydrolysis; Glucose; High solid loading; high solid loading enzymatic hydrolysis; High solid loading enzymatic hydrolysis; low cellulase addition; Low cellulase addition; Microwave-assisted extraction; microwave-assisted extraction (MAE); Organosolv pretreatment; Refining; Saccharification; Water solutions; γ-valerolactone/water delignification; Γ-valerolactone/water delignification
• Online Access: View Fulltext in Publisher

 Lignocellulosic biomass is a nonedible matrix that can be efficiently exploited as feedstock in an integrated biorefinery after a proper pretreatment. An organosolv pretreatment using an acidified γ-valerolactone (GVL)/water solution was proposed to improve the cellulose enrichment and enzymatic saccharification of cardoon (Cynara cardunculus L.) stems. At the optimal pretreatment condition (140◦C, 0.6 GVL/water, and 2.24% H2SO4), xylan was efficiently removed from the cardoon, and up to 50% of its content was recovered in the aqueous fraction, while 86% of the cellulose was retained in the solid fraction. The resulting cardoon pulp showed a cellulose content of 91.5% and an enzymatic digestibility of 100%. An overall glucose production of 37.17 g/100 g raw material (90% theoretical maximum) was obtained using high solid loading (20% w/w) and a high enzyme dosage (60 FPU/g cellulose). At a low enzyme dosage, glucose concentrations of 169 g/L and 210 g/L were achieved using 10 FPU/g cellulose and 20 FPU/g cellulose, respectively. Therefore, an organosolv pretreatment can be an effective process for producing cellulose-enriched pulp with enhanced enzymatic digestibility from cardoon stems, providing a promising option for green lignocellulosic biorefineries that aim to produce high concentrations of glucose with low cellulase addition. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.