Study of the production of bioethanol from hemicellulose hydrolyzed of sugarcane bagasse in fluidized-bed reactor and evaluation of the environmental impact generated by residues during the process

Abstract

This project is associated with the thematic project: "ETHANOL: Research and Development Aiming to an Integrated Use of Sugarcane Bagasse to Biotechnological Production of Lignocellulosic Ethanol" (FAPESP Process 2008/579264). Particularly, it is proposed the evaluation of new strategies for using the hemicellulose fraction of sugarcane bagasse aiming to its application in the production of biofuel liquid, the ethanol. It is also proposed the evaluation of the environmental impact of residues generated on this process. On a first step, specific techniques will be used to characterize the raw material, leading to soft hydrolysis with sulfuric acid of the hemicellulose fraction of the bagasse and its characterization in relation to its content of sugar and other toxic compounds. The hydrolyzed containing inhibitor compounds of microbial growing will be submitted to a process based on variation of pH and adsorption in active carbon. The residues generated on this step will be quantified and characterized aiming to its evaluation of its environmental impact. It may be included the evaluation of options for treatment of those residues. On the following step, the yeast Pichia stipitis NRRLY-7124 will be immobilized in calcium alginate using the technique of encapsuling. Preliminary experiments will be conducted on the fluidized-bed reactor aiming to determinate the important parameters such as minimum speed of fluidization and quantity of immobilized cells to be employed in the process. In the sequence, fermentations in batch systems will be conducted (factorial planning 23), aiming to the establishment and optimization of proper reactional conditions, in which there will be evaluated the influences of variables xylose concentration, co-substrate concentration and aeration flow. At the last part of the project experiments will be conducted with the reactor operating in continuous mode, aiming to evaluating the best performance on the production of ethanol in the fluidized-bed reactor. Specifically, the possibility of not being necessary to sterilize the reactional medium for the control of contamination aiming to the application of the studies process in industrial scale will be evaluated. Statistical planning techniques will be employed, when necessary, to evaluate and optimize the performance of the process. (AU)