Glycerol carbonate as green solvent for pretreatment of sugarcane bagasse

Abstract

BackgroundPretreatment of lignocellulosic biomass is a prerequisite for effective saccharification to produce fermentable sugars. In this study, “green” solvent systems based on acidified mixtures of glycerol carbonate (GC) and glycerol were used to treat sugarcane bagasse and the roles of each solvent in deconstructing biomass were determined.ResultsPretreatment of sugarcane bagasse at 90°C for only 30 min with acidified GC produced a solid residue having a glucan digestibility of 90% and a glucose yield of 80%, which were significantly higher than a glucan digestibility of 16% and a glucose yield of 15% obtained for bagasse pretreated with acidified ethylene carbonate (EC). Biomass compositional analyses showed that GC pretreatment removed more lignin than EC pretreatment (84% vs 54%). Scanning electron microscopy (SEM) showed that fluffy and size-reduced fibres were produced from GC pretreatment whereas EC pretreatment produced compact particles of reduced size. The maximal glucan digestibility and glucose yield of GC/glycerol systems were about 7% lower than those of EC/ethylene glycol (EG) systems. Replacing up to 50 wt% of GC with glycerol did not negatively affect glucan digestibility and glucose yield. The results from pretreatment of microcrystalline cellulose (MCC) showed that (1) pretreatment with acidified alkylene glycol (AG) alone increased enzymatic digestibility compared to pretreatments with acidified alkylene carbonate (AC) alone and acidified mixtures of AC and AG, (2) pretreatment with acidified GC alone slightly increased, but with acidified EC alone significantly decreased, enzymatic digestibility compared to untreated MCC, and (3) there was a good positive linear correlation of enzymatic digestibility of treated and untreated MCC samples with congo red (CR) adsorption capacity.ConclusionsAcidified GC alone was a more effective solvent for pretreatment of sugarcane bagasse than acidified EC alone. The higher glucose yield obtained with GC-pretreated bagasse is possibly due to the presence of one hydroxyl group in the GC molecular structure, resulting in more significant biomass delignification and defibrillation, though both solvent pretreatments reduced bagasse particles to a similar extent. The maximum glucan digestibility of GC/glycerol systems was less than that of EC/EG systems, which is likely attributed to glycerol being less effective than EG in biomass delignification and defibrillation. Acidified AC/AG solvent systems were more effective for pretreatment of lignin-containing biomass than MCC.

New efficient and recyclable catalysts for the synthesis of di- and tri-glycerol carbonates

“…It is used as a component of polyurethane foams, gas separation membranes, surfactants, paints, detergents and as a non-volatile reactive solvent for several types of materials. [47][48][49][50][51][52] Due to its low toxicity, vapor pressure and flammability, good biodegradability and moisturizing ability, glycerol carbonate also possesses the right characteristics of a wetting agent for cosmetic clays or of a carrier for drugs 53,54 Glycerol carbonate is usually prepared by reacting glycerol with toxic phosgene: 55,56 innovative processes such as the direct carboxylation of glycerol with carbon dioxide, 47,57-59 the glycerolysis of urea [60][61][62] or the trans-esterification reaction with linear or cyclic organic carbonates [63][64][65][66] represent ecofriendly alternatives. In recent years, multifunctional monomers based on glycerol carbonate have reached a particular importance in the chemical industry for the production of polyurethanes and polycarbonates (Fig.…”

The curious effect of potassium fluoride on glycerol carbonate. How salts can influence the structuredness of organic solvents

“…Nostro) lithium-ion batteries, cement and concrete industries, sugar cane treatment, cosmetics and detergents [1, [10][11][12].…”

Bio-Solvents: Synthesis, Industrial Production and Applications

“…Due to its favorable properties which include high polarity, boiling point (110-115°C) and flash point (109°C) and low vapor pressure, glycerol carbonate has interesting applications as a polar protic solvent, electrolyte liquid carrier, detergent solvent, humectant and nail polish/gel stripper [57]. It has also been demonstrated to serve as a promising solvent in pretreatment of sugarcane bagasse [13].…”

“…The main processing methods include biochemical and thermochemical conversion [7]. Using one or a combination of these processing techniques, several classes of bio-based solvents (including alcohols [9][10][11], esters [12,13], ethers [14], alkanes [15], aromatics [16] and neoterics [17,18]) can be manufactured (Figure 1).…”