Fractionation of rice straw by a single-step solvothermal process: Effects of solvents, acid promoters, and microwave treatment

Abstract

a b s t r a c tFractionation of lignocellulosic components is a primary step for maximizing value-added conversion of plant biomass to biofuels and chemicals. In this study, different organic solvents (methyl isobutyl keone, ethyl acetate, toluene and diethyl ether) in the ternary water/alcohol/organic solvent system and acid promoters (H 2 SO 4 , HCl, and H 3 PO 4 ) were studied on a single-step solvothermal fractionation of rice straw. Ethyl acetate was found to be a superior composite solvent to the conventional solvent MIBK by providing higher glucan and lignin yields. Glucan and xylan could be further solubilized and lignin recovery increased at higher temperature and acid concentration. The optimal fractionation conditions were found to be water/ethanol/ethyl acetate (62.5%:25%:12.5%) mixture using 0.05 M H 2 SO 4 at 160 C for 1 h, which gave cellulose-enriched solid with 71.4 wt% glucan yield. Hemicellulose (53.2 wt%) was obtained as sugars, and dehydration products in the aqueous/alcohol phase were minimal. 63.1 wt% lignin was recovered in the organic solvent phase with no cross-contamination of sugars. Microwaveassisted heating at 300 W, corresponded to the temperature of 160 C for 1 h resulted in comparable glucan and lignin yields in the respective phases to conventional heating with the advantages of increased pentose yield and lower furan formation in the aqueous phase.

Effect of various pretreatment methods on sugar and ethanol production from cellulosic water hyacinth

“…However, Das et al (2015) state the maximum theoretical ethanol yield as 0.3659 g/g of WH, which was 0.294 g/g of WH as reported by Cheng et al (2014). This is comparable to ethanol yields of other lignocellulosic materials, such as rice straw with 0.326 g/g (Imman et al 2015). Table 4 shows the ethanol productivity and yield by different types of pretreatment methods.…”

Nitric Acid Pretreatment of Jerusalem Artichoke Stalks for Enzymatic Saccharification and Bioethanol Production

“…lignin. The content of cellulose, the most important component, was comparable to that of other feedstock commonly used for bioethanol production, e.g., 36.3% for corn stover [41], 36.9% for sweet sorghum bagasse [33], 35.8% for rice straw [42], and 38.7% for wheat straw [43].…”

Irradiation Pretreatment of Tropical Biomass and Biofiber for Biofuel Production

“…The main goal of the pretreatment is to increase the enzyme accessibility and improve the digestibility of polysaccharides or carbohydrate available in the biomass [9]. The highly organized structure makes plant biomass recalcitrant to physical, chemical, and microbial attack [10]. Thus, the challenge of using lignocellulosic biomass is to have a fast and economical process by integrating variety of pretreatment during the conversion of biofuel.…”

“…Economically, biomass waste from palm oil plantation such as empty fruit bunch (EFB) can be used as resources for conversion of bioethanol, since the production is 6.1 million tons dry EFB and is forecasted to increase to 7.6 million tons in 2025 as shown in Currently, biorefineries are increasingly focused on integrated process design for maximum valorization of fractionated biomass components for fuels and a spectrum of co-products. This multi-product "integrated biorefineries concept" is a platform for development of modern biorefineries with economic competitiveness to the current petroleum industry [10]. According to the IEA (International Energy Agency) report from the assessment of available residue in 2030, it was predicted that 10% of global residues could yield around 155 billion lge (5.2 EJ) lignocellulosic ethanol or almost around 4.1% of the projected transport fuel demand in 2030, and 25% of global residues converted to either ethanol, diesel, or syngas that could contribute to 385-554 billion lge (13-23.3 EJ) globally [94].…”