Book Description

"The production of biofuels and biomaterials in the centralized biorefineries is challenged not only by the low bulk density material but also due to its variation in the availability and composition of the lignocellulosic part. Hence, on-farm production of denser and more uniform material for biorefinery operations is one of the solutions to address these problems. Under this circumstance, this study investigated the potential of steam-assisted and microwave-assisted treatments for the on-farm processing of lignocelluloses. Sweet sorghum bagasse was subjected to steam-assisted hydrothermal treatment (SAHT) for the extraction of hemicellulose. The optimized conditions of 12.5% (g/g) substrate concentration and 90 min of treatment at 121°C were conducive to the extraction of 72.69% (g/g) of the hemicelluloses and produced a hydrolysate containing 59.80 g/L reducing sugars. The SAHT-SSB was composed of 56.36% (g/g) cellulose and 31.42% (g/g) lignin. The hemicellulose-extracted residue was subjected to a steam-assisted lime treatment (SALT) to extract the lignin. The optimized conditions of 10% (g/g substrate) Ca(OH)2 and 106 min of treatment at 121°C extracted 69.67% (g/g) of the lignin from the SAHT-SSB, and produced a residue composed of 68.29% (g/g) cellulose and 13.26% (g/g) lignin. The extracted lignin was present in the yellow colored liquor. The CO2 treatment of the yellow liquor precipitated 58.85% (g/g) of the lignin present.Next, the SSB was subjected to microwave (MW)-assisted hydrothermal treatment (MAHT) at 121°C for the extraction of hemicellulose. The optimized conditions of 10% (g/g) substrate and 65 min of treatment time extracted 70.83% (g/g) of the hemicellulose from SSB. The hydrolysate contained 60.82 g/L reducing sugars and 2.98 g/L furfural. The solid residue was composed of 53.38% (g/g) cellulose and 30.19% (g/g) lignin. The MAHT-SSB was subjected to the MW-assisted lime treatment at 121°C for the extraction of lignin. Under the optimized conditions, lime at a concentration of 10% (g/g) of the substrate and 78 min of treatment residence time, 68.27% (g/g) of the lignin was extracted from MAHT-SSB. The MALT-SSB was composed of 69.41% (g/g) cellulose and 12.59% (g/g) lignin. The yellow-liquor was treated with CO2 and 60.26% (g/g) of the dissolved lignin was recovered.While comparing, the steam-assisted and MW-assisted methods have not exhibited differences in the overall recovery of solids, extraction of hemicellulose and lignin, and recovery of lignin and lime. The difference was found to be significant (p-value