Contents lists available at ScienceDirect Industrial Crops & Products journal homepage: www.elsevier.com/locate/indcrop Fractionation of sugarcane trash by oxalic-acid catalyzed glycerol-based organosolv followed by mild solvent delignification Chayanon Chotirotsukon a,c , Marisa Raita a,c, ⁎ , Verawat Champreda b,c , Navadol Laosiripojana a,c a The Joint Graduate School for Energy and Environment (JGSEE), King Mongkut’s University of Technology Thonburi, Prachauthit Road, Bangmod, Bangkok, 10140, Thailand b Enzyme Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), 113 Thailand Science Park, Phaholyothin Road, Khlong Luang, Pathumthani, 12120, Thailand c BIOTEC-JGSEE Integrative Biorefinery Laboratory, Innovation Cluster 2 Building, Thailand Science Park, Phaholyothin Road, Khlong Luang, Pathumthani, 12120, Thailand ARTICLE INFO Keywords: Biorefinery Glycerol-based organosolv Lignocellulose fractionation Organosolv lignin Sugarcane trash ABSTRACT Sugarcane trash (SCT) is an under-utilized biomass with potential for conversion to fuels and chemicals. Here, we report an organosolv process involving pretreatment by aqueous glycerol followed by mild delignification with acetone for fractionation of SCT. The effects of glycerol and oxalic acid on efficiency and selectivity of the reaction were studied at different temperatures. The higher glycerol content was found to promote delignifi- cation efficiency and enhanced enzymatic digestibility of the solid. An optimal reaction using 80%v/v glycerol at 170 ℃, with 300 mM oxalic acid followed by acetone extraction at 30 °C led to cellulose recovery of 71.7%, whereas 96.8% and 83.9% of the initial hemicelluloses and lignin was removed into the aqueous-glycerol and acetone fractions, respectively. The isolated lignin was recovered with 73.7% yield and 94.6% purity and showed similar chemical profiles with higher thermal stability compared to commercial organosolv lignin ac- cording to Fourier Transform Infrared Spectroscopy and Thermogravimetric analysis. 1. Introduction Biorefinery is an emerging industry for processing of renewable biomass into a spectrum of bio-products through integration of multi- disciplinary technologies. The integrated biorefinery process is focused on converting individual lignocellulose-derived components into com- binations of biofuels, biochemicals and biomaterials (Özdenkçi et al., 2017). All lignocellulosic biomass is composed of mainly three biopo- lymers, namely (i) cellulose, the linear polymer of glucose organized into a highly crystalline structure which is linked to (ii) hemicelluloses, the branched heteropolymer of pentose and hexose sugars which forms a network with (iii) lignin, the heteropolymer of phenolic alcohols that gives strength to the plant cell wall. This supra-molecular structure is highly recalcitrant to degradation (Chen, 2014). An efficient pretreat- ment step is thus required to disrupt the complex lignocellulose struc- ture before conversion of the biomass. This results in separation of the hemicellulose and lignin fractions, resulting in cellulose fibers with increased enzymatic digestibility for subsequent conversion. Sugarcane is a major crop worldwide with a high lignocellulosic content. Sugarcane trash (SCT) is a potential substrate for biorefinery. In general, SCT refers to sugarcane tops and leaves left on the field after harvesting, which represents approximately 18% of the total above ground biomass and about 14 tons per hectare of the crop yield (Leal et al., 2013). Despite having a similar energy content to sugarcane bagasse, which is currently used as fuel in boilers, SCT is frequently burnt or left in the field. The use of SCT as a biofuel is limited by technical concerns on its processing due to its high mineral content, which can result in surface deposition and corrosion problems in pro- cessing machines (Nakashima et al., 2017; Smithers, 2014). Open-field burning of SCT is a major source of air pollution, and sugarcane pro- ducing countries are increasingly prohibiting this practice to reduce negative environmental impact (Capaz et al., 2013). Restrictions on SCT burning will increase the availability of SCT for use as a raw ma- terial in biorefinery, which can generate additional economic benefits to the sugar-based biorefinery industry (Seabra et al., 2010). Lignin is recognized as an underused fraction among the three major structural constituents of lignocelluloses due to its structural com- plexity (Dien et al., 2009). Organosolv pretreatment is a promising https://doi.org/10.1016/j.indcrop.2019.111753 Received 22 May 2019; Received in revised form 26 August 2019; Accepted 2 September 2019 ⁎ Corresponding author at: The Joint Graduate School for Energy and Environment (JGSEE), King Mongkut’s University of Technology Thonburi, Prachauthit Road, Bangmod, Bangkok, 10140, Thailand. E-mail address: marisa@jgsee.kmutt.ac.th (M. Raita). Industrial Crops & Products 141 (2019) 111753 0926-6690/ © 2019 Elsevier B.V. All rights reserved. T