A biorefinery approach for fractionation of Miscanthus lignocellulose using subcritical water extraction and a modified organosolv process. (April 2018)

• Record Type: Journal Article
• Authors: Muniz Kubota, Arielle; Kalnins, Raitis; Overton, Tim W.
• Is Part Of: Biomass and bioenergy. Volume 111(2018)
• Page Start: 52
• Page End: 59
• Publication Date: 2018-04
• Subjects: Subcritical water -- Principal component analysis -- Delignification -- Biofuel -- Biorefinery; MxG Miscanthus x giganteus -- SWE Subcritical water extraction -- PCA Principle component analysis; Biomass energy -- Periodicals; Biomass -- Periodicals; Energy-Generating Resources -- Periodicals; Bioénergie -- Périodiques; 333.9539
• DOI: 10.1016/j.biombioe.2018.01.019
• Languages: English
• ISSNs: 0961-9534

Abstract

Abstract: Using a biorefinery approach, biomass polymers such as lignin and carbohydrates can be selectively purified from lignocellulosic feedstocks with the aim of generating not only lignocellulosic bioethanol but also high value bio-based compounds. Furthermore, the efficient use of the entire biomass can increase overall feedstock value and significantly contribute to process cost-effectiveness. Therefore, the aim of this work was to fractionate the main compounds of the energy crop Miscanthus x giganteus (MxG) using 'green' solvents in order to obtain cellulose-enriched fibres as well as non-toxic streams rich in hemicellulose and lignin. Two processing routes were compared: a direct 1-step modified organosolv method for simultaneous lignin and hemicellulose removal; and a 3-step sequential process using subcritical water extraction for recovery of first extractives then hemicellulose, followed by modified organosolv lignin extraction. Both methods successfully generated cellulose-enriched fibres; from a complex mixture of compounds present in MxG, it was possible to obtain fibres comprising 78% cellulose without the use of commonly-applied toxic solvents that can potentially limit end uses for processed biomass and/or need additional neutralization steps. Fibres generated by the direct and sequential processes were very similar in composition; however, physicochemical analysis of the fibres using scanning electron microscopy, Fourier-transform infrared spectroscopy and principal component analysis confirmed structural differences resulting from the two processing routes, which were demonstrated to have an impact on downstream processing. Highlights: Two processing routes using green solvents were used to fractionate Miscanthus. Purified cellulose fibres were analysed using physicochemical & statistical tools. Different processes generated fibres with different physicochemical properties, which impacted in downstream processing.