Comparison of dilute acid and ionic liquid pretreatment of switchgrass: Biomass recalcitrance, delignification and enzymatic saccharification

• Published in: Bioresource technology Vol. 101; no. 13; pp. 4900 - 4906
• Main Authors: Li, Chenlin, Knierim, Bernhard, Manisseri, Chithra, Arora, Rohit, Scheller, Henrik V., Auer, Manfred, Vogel, Kenneth P., Simmons, Blake A., Singh, Seema
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.2010; [New York, NY]: Elsevier Ltd
• Subjects: acid treatment; Acids; Acids - chemistry; beta-glucosidase; Biomass; Carbohydrates; Carbohydrates - chemistry; cellulases; cellulose; Cellulose - chemistry; chemical composition; chemistry; Comparison; Dilute acid; enzymatic hydrolysis; Enzymatic saccharification; Glucans; Glucans - chemistry; Hydrolysis; Ionic liquid; Ionic Liquids; Ionic Liquids - chemistry; lignin; Lignin - chemistry; methods; Microscopy, Electron, Scanning; Microscopy, Electron, Scanning - methods; Panicum virgatum; Pretreatment; saccharification; Solvents; Solvents - chemistry; Spectroscopy, Fourier Transform Infrared; Spectroscopy, Fourier Transform Infrared - methods; Spectrum Analysis, Raman; Spectrum Analysis, Raman - methods; sulfuric acid; Time Factors; X-Ray Diffraction; Dilute acid; Pretreatment; Enzymatic saccharification; Comparison; Ionic liquid
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2009.10.066

The efficiency of two biomass pretreatment technologies, dilute acid hydrolysis and dissolution in an ionic liquid, are compared in terms of delignification, saccharification efficiency and saccharide yields with switchgrass serving as a model bioenergy crop. When subject to ionic liquid pretreatment (dissolution and precipitation of cellulose by anti-solvent) switchgrass exhibited reduced cellulose crystallinity, increased surface area, and decreased lignin content compared to dilute acid pretreatment. Pretreated material was characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and chemistry methods. Ionic liquid pretreatment enabled a significant enhancement in the rate of enzyme hydrolysis of the cellulose component of switchgrass, with a rate increase of 16.7-fold, and a glucan yield of 96.0% obtained in 24h. These results indicate that ionic liquid pretreatment may offer unique advantages when compared to the dilute acid pretreatment process for switchgrass. However, the cost of the ionic liquid process must also be taken into consideration.