Utilização do hidrolisado ácido e enzimático produzido a partir de resíduos vegetais obtidos em feiras abertas da cidade de Manaus para produção de bioetanol

Abstract

The increased use of fossil fuels has enhanced the interest in obtaining renewable and low-cost fuels such as bioethanol. Lignocellulosic plant residues can be hydrolyzed and yield fermentable sugars. This master's project aimed to investigate the use of acid and enzymatichydrolyzed produced from plant residues for bioethanol production obtained in an open market-place from Manaus city. For that reason, the following wastes were investigated: tucumãpeel (Astrocaryum aculeatum), cupuaçu peel (Theobroma grandiflorum), peach palm peel (Bactris gasipaes), açaí seed (Euterpe oleracea) and cassava peel (Manihot esculenta). Then, all these wastes were submitted to acid and enzymatic hydrolysis, after it was performed the characterization of monomers, furfural and hydroxymethylfurfural of all hydrolyzed and the most suitable was conducted tofermentation and optimization of sugars obtainment. Fermentation process of hydrolysates was conducted with the yeast Saccharomyces cerevisiae strain PE-2 for 72 hours at 25 ° C. In addition, for optimization of the acid hydrolyzed obtainment process, an experimental design was conducted to evaluate the influence of hydrolysis time, ratio g H2SO4 / g of peel and the solid-liquid ratio required to obtain a hydrolyzate with higher concentrations of sugars and lower levels of furfural. Further, it was performed oneexperimental design, the optimization to obtain an enzymatic hydrolyzate process. The factorial design evaluated the performanceof the enzyme Celluclast® 1.5L at different concentrations,time and temperature. As a result, the characterization of enzymatic and acid hydrolysates showed the peach palm peel has great glucose levels 56.55 g L-1 and 23.5 g L-1, respectively.After the fermentation process, thepeach palm acid hydrolyzate produced 29.2 g / L of ethanol theoretically and thepeach palm enzimatic hydrolyzate produced 12,9 g / L.For maximal production of sugars and furans tolerable levels the optimal concentrations for the acid hydrolyzate were ratio of 0.63 g H2SO4 / g peel and solid-liquid ratio of 0.1707. However, for production of sugars from the enzymatic hydrolyzate the enzyme Celluclast® 1.5 L in the concentration of 1223.4 U / g, 51.2 ° C and 59.75minutes of hydrolysis showed the outstanding performance releasing 3.24 g/L of sugars from peach palm peel. Thus, this study highlights the potential use of acid andenzymatic hydrolyzate of peach palm peel as substrate for the production of bioethanol.

Keywords: starchy substrates, saccharification, ethanol