(625ab) Bioethanol Production from Guinea Grass (Panicum Maximum) Using Ionic Liquid

Due to growing global energy demand and concerns about future shortage of non-renewable energy, the development of new technologies to produce fuel from renewable energy sources is seen as a good solution to the challenges of next generations. This work focused on the study of two important stages of bioethanol production route, pretreatment and saccharification of guinea grass (Panicum maximum cv.), which is a biomass composed mainly of lignin, cellulose and hemicellulose. Although there is already technology to produce ethanol from other lignocellulosic compounds, such as wheat straw and sugarcane bagasse and straw, no previous reference was found on the use of guinea grass as raw-material, which motivated research on the topic. The grass was dried and ground and its characteristics regarding the average particle size and moisture content were determined. The biomass was submitted to a pre-treatment using the ionic liquid 1-ethyl-3-methyl imidazolium acetate to possibly increase the access to the cellulose fibers. This pre-treatment was carried out at different times, temperatures and concentrations to assess the optimum point of delignification, which means, the operational condition that could maximize enzymatic hydrolysis stage as much as possible. In addition to lignin content, the pre-treated grass as well as the non-pre-treated grass had their holocellulose, cellulose and ash content analyzed. The next step evaluated was the enzymatic hydrolysis of non-pre-treated and pre-treated grass on 20 FPU / g of substrate. The best condition achieved for pre-treatment resulted in the conversion of 69.8% of glucose and 54.2% of reducing sugars, respectively, analyzed via DNS method and Kit Glucose LABTEST Liquiform method. It was tested the acid hydrolysis of pre-treated grass with sulfuric acid 1M, temperature of 120°C and time reaction of 2 hours. The result was the conversion of 27.2% of reducing sugars and 57.4% of glucose. It was used Saccharomyces Cerevisae cells to proceed the fermentation of reducing sugars obtained through the pre-treatment (best condition studied in this work) and enzymatic hydrolysis of the material and the amount of ethanol was determined by gas chromatography. The global process result was the production of 70.4 grams of ethanol per kilogram of green grass.