CHARACTERIZATION OF CELL WALL POLYSACCHARIDES AND CELLULOSIC ETHANOL POTENTIAL IN GENOTYPES OF SORGHUM BIOMASS

The physicochemical characterization of the cell wall polysaccharides of different genotypes of sorghum bicolor, (Sorghum bicolor (L.) Moench) was obtained using the raw biomass and after the chemical pretreatments, with the objective of this culture being a potential source for the production of cellulosic ethanol. Among the evaluated genotypes two hybrids brown midrib (bmr) sorghum biomass (2015002 and 2015003) were tested compared to three conventional sorghum biomass hybrids (CMSXS7927, CMSXS7016 and BRS716). The lignocellulosic composition of the biomass of the bmr hybrid 2015B002 and 2015B003 stood out, presenting significantly lower lignin contents (4.63%) than the conventional hybrids (7.15%). The results showed that the acid treatment followed by the alkaline treatment showed the best performance after the enzymatic hydrolysis, supported by the Scanning Electron Microscopy (SEM), Fourier Transform Infrared Analysis (FTIR), Thermal analysis (TG) and crystallinity index analyzes. Cellulosic ethanol production for the evaluated hybrids ranged from 6,612 to 11,838 liters per hectare per cycle of 180 days. Biomass sorghum bmr 201556B002 presented better hydrolysis yield for the two types of saccharification used when compared to conventional genotypes. The yield of ethanol using this mutant hybrid reached 11,838.46 L ha-1, demonstrating the potential of this biomass.