SORGHUM GENOTYPES WITH POTENTIAL FOR SACCHARIFICATION

Conversion of lignocellulosic biomass into ethanol requires a pretreatment step to remove lignin, hemicellulose and to reduce cellulose crystallinity. The pretreatment makes cellulose more available to enzymatic hydrolysis (saccharification), increasing glucose content, which will be used in the next fermentation step. This work aimed to analyze the chemical composition and saccharification potential of five sorghum genotypes developed by Embrapa, differing on bioenergy related traits: two high biomass brown midrib (bmr) mutant lines (201552B03 and 201552B18), a high biomass hybrid (BR716), a commercial sweet sorghum line (BRS511) and an experimental biomass-sweet sorghum genotype (201641B-138). The sorghum samples were pre-treatment with H2SO4, and the glucose yield was obtained after enzymatic hydrolysis. The glucose content was analyzed by HPLC.
While brown midrib lines (201552B03 and 201552B18) presented the highest levels of hemicellulose (27.8 and 27.9 % w/w respectively), they also showed the lowest levels of lignin content (4.0 and 5.7 % w/w respectively) as did BRS511 (5.8 % w/w). Consequently, saccharification efficiency was higher in these genotypes and 201552B003 yielded the highest glucose content after 72 hours of saccharification (0.166 g.g-1). These results contribute to the current knowledge on biomass sorghum, as a suitable biomass source for fermentable sugars production.