Obtainment and Characterization of Lignin from Enzymatic Hydrolysis of Sugarcane Bagasse of 2G Ethanol Process in Pilot Scale

A promising use of sugarcane bagasse is for cellulosic ethanol production. One step of this production is the enzymatic hydrolysis process. A residual stream from this process is mainly composed of lignin and some non-hydrolysed cellulose fibers. In order to extend the application of the biorefinery concept to second generation (2G) ethanol production, the residue generated in this process could be used as raw materials for new processes to obtain value-added products. Besides, fully utilization of the residues produced in the enzymatic hydrolysis process is a feasible method to reduce cost. Lignin has a potential to replace petroleum-based materials, which are increasingly scarce and expensive, in many industrial applications, such as phenolic resins. The original source, the extraction method used and the process by which lignin was stemmed change its physicochemical characteristics. Thus, the suitability of lignin as raw materials into value-added products can vary widely. Bearing all these in mind, it is necessary to characterize the material to be able to evaluate it in formulations of value-added products. In this work, a chemical characterization of Enzymatic Hydrolysis Residue Lignin (EHRL) was carried out aiming the use for resins. The EHRL was obtained from the sugarcane bagasse pretreated by hydrothermal process to 190 degrees C by 10 min with solid-liquid ratio of 1:10. Then, the enzymatic hydrolysis process was carried out using the 15 FPU/g dry biomass of cellulolytic complex (Celluclast (R) 1.5 L) and 10 UI/g dry lignocellulose of beta-glucosidase (Novozym (R) 188). The pretreatment and the enzymatic hydrolysis processes were carried out in batch reactor (Pope Scientific 350 L) pilot scale using the facilities of Brazilian Bioethanol Science and Technology Laboratory (CTBE). A chemical characterization of the EHRL allowed knowing better its features, before being applied in manufacturing of value-added products. By chemical characterization method, we found that the total lignin content is 47.3 %, cellulose content is 39.8 %, hemicelluloses content is 4.5 % and ash content is 8.4 % (w/w on dry matter) in the EHRL. An alternative to use the EHRL for manufacturing of composites has been considered. Since it could be used to partially replace petroleum-based phenol in synthesis of phenolic resins, it is interesting to evaluate the effect of the remaining cellulose fibers in the EHRL and as they could act as reinforcement in phenolic composites.