The use of lignocellulosic biomass for obtaining biofuels and other based on microbial fermentation is a promising approach. Rice (Oryza sativa L.) has worldwide importance, being its husks one of the most abundant agricultural wastes of the world. Because it abundance and low cost, rice husks may be promising prime matter for fermentative processes. The aim of this research work was to evaluate the hydrolysis of Rice husks produced in Roraima, North of Brazilian Amazonia, for obtaining fermentable sugars using enzymatic or acid hydrolysis. Triturated or intact Rice husks were treated with sulfuric acid and freeze-dried α-amylase of Aspergillus oryzae, both using factorial design experiment, being total reducing sugar used as response variable. Acid hydrolysis presented highest total reducing sugar yield and total reducing sugar concentration of 163.71 g.kg-1 and 33.97 g.L-1, respectively. These results were obtained using intact husks, sulfuric acid concentration of 1.5% and solid: liquid ratio of 1: 8. Time was not significant factor. Enzymatic hydrolysis presented highest total reducing sugar yield and total reducing sugar concentration of 91.57 g.kg-1 and 19.00 g.L-1, respectively, obtained when using triturated husks. Subsequent efforts should be employed to establish hydrolysis processes that may be used on rice processing industries.
Keywords: α-amylase, Aspergillus oryzae, lignocellulosic waste, Oryza sativa, reducing sugar, sulfuric acid.