Cinética de sacarificación y fermentación para producción de bioetanol a partir de cáscara de banano maduro mediante pretratamiento de secado.

Abstract

The objective of this study was to determine the kinetics of bioconversion of the ripe banana peel in bioethanol, by saccharification and alcoholic fermentation, taking advantage of the organic waste in this case the banana peel to obtain a biofuel to cope with the shortage of Non-renewable energy sources. The characterization of the lignocellulosic components of the banana peel was determined by thermogravimetric analysis to know the initial percentage of Lignin, Cellulose and Hemicellulose, which was 21.12 ± 0.24%, 19.33 ± 0.28% and 11.43 ± 0, 39% respectively. The "banana peels" were requested in the company "Diana Food", located in the parish of the city of the city. Past, these times were also transported in the research laboratory to select the husks in the same degree of maturation to be previously dried in an incubator at 70 °C for 4 days. Subsequently, its particle size was reduced by mechanical grinding to 250 μm mesh. The mixture of the cellulose substrate at 5% w / v and the water was subjected to a constant agitation for 24 hours, at a pH of 4.8 and a temperature of 40 °C. Under these conditions, the commercial enzyme cellulase is obtained in the lignocellulosic substrate for perform enzymatic hydrolysis. The amount of reducing sugars produced during this aerobic process was determined by the dinitro salicylic acid (DNS) method by colorimetry with a UV-Visible spectrophotometer with a wavelength of 540 nm. For this, see 3 treatments in relation to the amount of inoculum for enzymatic hydrolysis, which were 30 μL/g of processed substrate (D1), 60 μL/g of processed substrate and 90 μL/g of processed substrate respectively. Obtaining better results at 4 hours of enzymatic hydrolysis with the D1 treatment with a yield of reducing sugars of 4750 ppm. For alcoholic fermentation, the enzyme was previously inactivated in an autoclave set at 121 °C within 15 min. Then, over 4 days (96 h) using the yeast as inoculum, Saccharomyces cerevisiae was previously activated at 37 °C with 10% sucrose for 48 hours. This inoculum was added to the glucose to the correct response of the enzymatic hydrolysis process (1 ml of activated yeast / 1000 ml of hydrolyzate). The bioethanol was quantified by gas chromatography with a retention time of 3 minutes in one area (UV*s) of 993976.9. The result was 11050 ppm of reducing sugars (11.05 ± 0.44 g / L) and 7609 ppm of ethanol (7.6 ± 0.17 g/L). To determine the constant of the speed, a kinetic model of Monod was used, which resulted in a kinetic constant of saccharification that of K = 0.169 g/L∙h, while the kinetic constant of alcoholic fermentation was K = 0.697 g/L∙h. Demonstrating that a physical pretreatment allows us to perform a better bioconversion of the lignocellulosic components of the ripe banana peel to obtain bioethanol.