PRE-TREATMENT WITH HYDROCHLORIC ACID AND ENZYMATIC HYDROLYSIS OF SUGAR CANE BAGASS TO OBTAIN GLUCOSE (Atena Editora)

Abstract

Pretreatment and enzymatic hydrolysis are two important steps within the process of converting lignocellulosic biomass into glucose. In this work, sugarcane bagasse (BCA) ground into particles smaller than 40 mesh (< 425 µm) was pre-treated with hydrochloric acid (HCl) in different concentrations (0.75, 1.0 and 1.25 mol/L), in time varying from 30 to 90 min by autoclaving (121 ºC / 1 atm) in solid ratio :net 1:10. The pretreated BCA was subjected to hydrolysis with commercial enzymes at a solid:liquid ratio of 1:30, with100 µL of cellulase mixtures and 100 µL of Aspergilus niger laccase, in citrate-phosphate buffer (50 mM; pH 4.8) for 72h at 50 ºC under agitation at 150 rpm. Pre-treatment with HCl showed an efficiency in delignification of BCA of 59.2% and the glycan fraction increased to 64.48% in the solid residue of BCA recovered after pre-treatment carried out with HCl 1.25 mol/L, time 30 min. Within these operational parameters, enzymatic hydrolysis continued for 72h. Within a mass balance analysis, a solids recovery of 42.8% was observed for the pre-treatment stage with HCl. Therefore, for every 100 g of pre-treated BCA, within the process, residue with 64.48 g of glycan and 9.23 g of lignin was recovered and for every 100 g of BCA recovered after pre-treatment and enzymatically treated with cellulases and laccase it was possible to obtain 12.0g of glycan hydrolyzed into glucose. It is concluded that pre-treatment with dilute acid and hydrolysis with commercial enzymes showed efficiency in converting BCA glycan into glucose.