Response surface for sugars extracted from lignocellulosic material providing low energy expenditure

Abstract

The objective of this work was the extraction of sugars from the sugarcane bagasse from the chemical pretreatment with diluted sulfuric acid, with a factorial planning of 3 factors with two levels each. The levels of 5 and 15 g for sample mass, two variations of 5 and 10% acid concentration and 25 and 50 oC temperature variations were adopted. The characterization of the hydrolyzate was done through the refractive index and by high performance liquid chromatography. For the refractive index, the tests 3, 7 and 8 had the highest amount of soluble solids extracted, being 13.005; 13.025 and 13.010 oBrix, respectively. According to the effects obtained from the results of the refractive index, the only significant main effect is the increase in acid concentration, which increases the refractive index. In the results obtained by liquid chromatography, we were able to identify the presence of glucose, xylose and cellobiose in the solutions and the condition that resulted in a higher extraction of sugars was: 15 g biomass, 10% acid concentration and temperature at 50 oC. With the concentration of the acid in the upper limit (10%) the sugar extraction in this work was significant with 13.025 gL -1.

Keywords

• sugarcane bagasse
• factorial planning
• chemical pre-treatment.