Pré-tratamento alcalino e radiação de micro-ondas em Brachiaria brizantha para a produção de etanol

Abstract

The second-generation of biofuels have higher potential than many of the first generation biofuels on many aspects. Our objective was to study the feasibility of association between the alkaline chemical pretreatment and microwave radiation forbioethanolproductionfrom Brachiariabrizanthacultivate marandu. Biomass samples were cleaned, washed and milled, and kept under refrigeration until use.A factorial design evalueted the impact of alkali concentration (NaOH), Liquid/Solid ratio, irradiation time and irradiation potency.Cellulose, Hemicellulose and Lignin contents were determined for every experimental condition.Cristallinity Index was calculated from X Ray Difratograms. Reducing sugars content was determined by DNS colorimetric method. Enzymatic hydrolysis were performed on the raw and pretreated sugarcane bagasseand released reducing sugar content were determined.The lignocellulosic material showed excellent results when subjected to pre-treatment, obtaining amounts of cellulose three times higher (64.65%) compared to material without pre-treatment (22.8%) andwith a 67.3% of delignification.This suggests that the association between the microwave radiation and alkaline pre-treatment shows great potential for bioethanol production. The maximum amount oftotal reducing sugars released (g L-1) obtained with the alkaline pre-treatment followed by microwave radiation was14.09 g L-1, whereas the material without pre-treatment reached 8.95 g L-1.