Hydrochloric acid-catalyzed hydrothermal pretreatment of brown seaweed residues for enhancing biofuel production

Abstract

The hydrochloric acid-catalyzed hydrothermal pretreatment of brown seaweed residues (Laminaria japonica) was optimized with respect to three operating factors: temperature, time, and the concentration of HCl, using response surface methodology (RSM). In order to confirm the significance of the quadratic model, an analysis of variance was performed, which resulted in an F-value of 11.09. Therefore, the regression model was highly significant. Additionally, the pareto chart was used to contrast the absolute values of the standardized effects. Response surface and contour plots were used to illustrate a surface with a maximum. The perturbation plot showed the sensitivity of the reducing sugars yield to the independent factors. Under the reaction conditions of 142 °C, 9 °C, 18.6 min, and 0.1 N HCl concentration, the experimental yield of 113.0 mg/g and the predicted yield of 107.5 mg/g were obtained.