Obtención de bioetanol a escala de laboratorio a partir de residuos de cáscara de piña generados en el Departamento de Santander

Abstract

The accumulation of solid waste, generated mainly by rural and urban development, offers an environmental threat, since problems such as: presence of rodents and insects vectors of diseases, bad odors from decomposition of waste, contamination of water sources and atmospheric, landscape deterioration, among others (Narea, 2008). However, solid waste offers a biotechnological opportunity, related to the use of the lignocellulosic material it contains; Thanks to them, these can be used as a carbon source in fermentation processes with microorganisms and thus obtain value-added products such as ethanol, which can be widely used in industries such as pharmaceuticals, cosmetics, fuels and energy, among other. (Vargas, 2016) (Cheng & Wang, 2013) The objective of this work was to take advantage of the residues of the pineapple peel (Gold honey varieties, Perolera and its mixture 50-50% w / w), after oxidative pretreatment and enzymatic hydrolysis process, to transform the lignocellulosic material into sugars. Simple fermentables, and from these, by anaerobic action of S. cerevisiae yeast, produce second generation ethanol. In order to establish the best operational conditions for obtaining the lignin present in the organic waste to be used, a design 23 was applied, from which the best conditions were established for the concentration of hydrogen peroxide (H2O2), time and temperature, for the pretreatment in the laboratory of the pineapple residues of the varieties Oro honey and Perolera (7%, 1h and 25 ° C) and (3%, 1h and 25 ° C), respectively. After the enzymatic hydrolysis process and the obtaining of the glucose syrups with a yield of degradation of the biomass (w / w) by the action of the CellicCTec2 enzyme of 54%, a process in which the hemicellulose and cellulose present are degraded into monosaccharides that will be subsequently fermented. For the fermentation process, a statistical factorial design 23 was carried out, for the production of ethanol through anaerobic fermentation with the S. cerevisiae yeast, from this design, they were established for the two varieties of pineapple residues and their mixture (50:50 p / p), as best fermentation conditions 30 ° C, 36 h reaction, pH 5,5 and constant stirring at 210 rpm. The concentration of ethanol obtained from the fermented syrup was 10,8 gL-1 for the Oro Oro variety, 10,6 gL-1 for the Perolera variety and 12,3 gL-1 for the mixture of these (% 50- 50 w / w), starting from a glucose concentration of 20,2; 22,7 and 26,1 gL-1 respectively. Additionally, through Life Cycle Analysis, the environmental impacts generated in each of the stages of the process (adaptation of the plant material, pre-treatment, enzymatic hydrolysis and fermentation) were considered, with which it was observed that the energy expenditure in the stage of the pretreatment process had the greatest impact.