Treatments to improve obtention of reducing sugars from agave leaves powder

Abstract

The leaves of agave plant (Agave tequilana Weber) are agricultural crop residues with a high content of carbohydrates represent a potential feedstock for biofuel production. The objective was to study the effect of treatment conditions in agave leaves powder (dried at 100 °C, particle size ≤0.3 mm) to improve the conversion of carbohydrates from lignocellulosic material and fructans to monosaccharides. Lignocellulosic material was pretreated using dilute acid (H2SO4 or HCl) at different concentrations (0.5%–2.0% v/v) and enzymatic hydrolysis was performed using four commercial enzymes Viscozyme, Cellic HTec, Celluclast, and Cellic CTec-2 separately. In addition, the enzymatic hydrolysis reaction (pH 5.0, 50 °C) using the commercial cellulases were evaluated at different times (0–36 h) in the lignocellulosic material. Fructans were extracted from agave powder and hydrolysates using a commercial inulinase preparation, Fructozyme L, (pH 5.0, 50 °C, 24 h). The best results of the treatments applied in the lignocellulosic material were H2SO4 (0.5% v/v) and enzymatic hydrolysis using Cellic CTec-2 for 18 h. The sugars released from the lignocellulosic material and the fructans represent a saccharification yield of 97%, obtaining 68 g of reducing sugars per 100 g of agave powder. The furfural and hydroxymethylfurfural compounds were not detected in the lignocellulosic material treated with H2SO4 (0.5% v/v) and the concentration of phenolics was 239.8 ± 2.1 mg/L. The results show that the treated agave leaves represent a good prospect for the production of biofuels.