Sugarcane is a plant largely produced in Brazil. The plant is crushed to recover sucrose and the bagasse residue can be used for the production of second-generation ethanol, among other possible products. Bagasse is basically composed of cellulose, hemicellulose, and lignin, forming a complex structure that is recalcitrant to direct hydrolysis by enzymes. Previous studies show that the most limiting factor for converting the polysaccharides into monomers is the barrier imposed by lignin. The regions of the sugarcane internode with high lignin contents are the most recalcitrant. Based on previous work, the proposed project intends to test a new sugarcane-processing model where the most recalcitrant region corresponding to the outermost fraction of the "stalk" of the cane (rind and outer cortex) would be separated from the inner region. The outermost fraction could, in principle, be allocated to the direct combustion for power generation. The innermost part (less recalcitrant) after the extraction of sucrose would be pretreated in mild process conditions, potentially resulting in materials susceptible to enzymatic hydrolysis. To evaluate this concept it is proposed to use three experimental sugarcane hybrids, which contrast in chemical composition to be pre-treated by a process employing alkaline sulfite as delignification agent. The pre-treatment will be done in various conditions in order to check whether it is possible to minimize the requirement for chemicals in the pretreatment step of the innermost regions when compared to more external regions. The development of this proposal is linked to the FAPESP project 2014/06923-6 entitled "Recalcitrance of biomass from sugarcane: Fundamentals related to the formation of cell walls, the pretreatment, and enzymatic digestion, used to develop new models of biorefineries".
News published in Agência FAPESP Newsletter about the scholarship: