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This work aimed to study the fractionation of sugarcane bagasse using a two-step hydrothermal and ethanosolv process in a flow-through reactor system. The effects of reaction temperature with or without acid addition were studied based on the removal, recovery, and yield of biomass components in both solid and liquid phases. Increasing the temperature from 150 to 190 °C with H 2 SO 4 adjusted to pH 2 in the first hydrothermal step followed by the ethanosolv step using a mixture of ethanol:water (95:5 v/v) for 48 min with a constant flow rate of 25 mL/min led to increasing trends of hemicellulose and lignin removal in ranges of 79.1−98.5% and 62.4−95.6%, respectively, while a decrease in the remaining cellulose residues in the range from 87.8 to 40.5% was observed. This corresponds to yields of hemicellulose and lignin obtained in the liquid phase being in ranges from 42.9 to 63.8% and from 44.2 to 61.0%, respectively. Operation at 170 °C with acid supplementation in the hydrothermal step followed by an ethanosolv process was found to be the optimal conditions for the efficient removal of hemicellulose and lignin with high cellulose recovery. The developed process can be applied for efficient fractionation of bagasse in biorefineries.

Cellulose-based composites are promising biomaterials with potent applications in absorbents, cosmetics, and healthcare industries. In this study, the cellulose fractions from various agricultural residues, including bagasse (BG), rice straw (RS), corncob (CC), and palm fiber (PF), were prepared by the organosolv process using 70% v/v ethanol, followed by bleaching and forming with chitosan powder. Organosolv treatment at 180 °C of BG, RS, and PF and at 190 °C of CC for 60 min using H2SO4 as the catalyst was optimal for high cellulose recovery (87.9–98.9%) with efficient removals of the hemicellulose (59.3–86.0%) and lignin (61.1–73.7%). High cellulose purity in the solids (76.9–86.8%) was obtained after bleaching with 4% v/v H2O2 compared with that of 84.9% for commercial cellulose. The isolated celluloses were incubated with 2% w/v chitosan solution in acetic acid for the formation of the hydrogen-bonding interaction between the cellulose fiber and chitosan. The pieces of evidence of the obtained sheet materials were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction analysis, and thermogravimetric analysis. All cellulose–chitosan materials absorbed water fraction in the range of 54.3–94.2 g/m2. Efficient oil absorption was observed for cellulose–chitosan sheets prepared from PF (96.3 g/m2) and CC (81.1 g/m2). This work demonstrated the preparation of potent biobased absorbents with a promising application in waste treatment and healthcare industries.

Organosolv lignin is an emerging bio-additive for creating functional properties in various products with its advantages in high-purity, sulfur-free, biocompatibility, and solubility in green solvents. In this study, effects of thermal and physical modification on alterations of functional properties and particle size distribution of isolated organosolv lignin from sugarcane bagasse (OLB) were studied. Thermal treatment of OLB at increasing temperatures from 170 to 230°C in 70%w/w aqueous ethanol led to alteration of phenolic hydroxyl content, while ultrasonication resulted in homogeneous size distribution of the modified OLB according to laser diffraction and scanning electron micrograph. The highest ultraviolet light absorbance and antioxidant activities were obtained at 190°C treatment which were correlated to the highest phenolic group content. Application of the modified OLB at 3% w/w in a base cream formulation resulted in enhancement of the anti-UV activity to exceed SPF 50 with increasing antioxidant activity in the product. The work provides basis on modification of organosolv lignin for application as a potent functional additive in cosmeceutical products.