Avaliação do uso biotecnológico da casca de coco e seu potencial para produção de xilitol

Abstract

The industrial production of coconut water generates a significant amount of green coconut shell waste, whose inadequate disposal causes significant environmental impacts such as soil pollution and landfill overload. This study evaluates the general biotechnological potential of coconut shells and also for the production of xylitol, a low glycemic index sweetener with antimicrobial properties, widely used in the food and pharmaceutical industries. Initially, a bibliographic review was carried out on the use of agro industrial waste and the development of extraction methods for fermentable compounds using the search for studies in the Scopus and Web of Science research platforms in order to analyze their potential for the extraction of sugars from green coconut shells, offering a basis for carrying out experiments with the flour from its shell, with pretreatment using diluted sulfuric acid at different concentrations and times in order to obtain an optimized condition by the RSM method to reduce the use of resources and time, it was allowed to obtain the optimized condition of 0.94 M H2SO4 and a time of 21.36 minutes, allowing the obtaining of the value 11.45 ± 0.06 of xylose. The fermentation was carried out using the microorganism Kluyveromyces marxianus ATCC 36907, under conditions of 30 oC and 200 rpm, to evaluate the conversion of xylose to xylitol. The production kinetics showed that the initial glucose consumption was efficient, favoring cell growth and ethanol production (5.68 g/L in 48 hours), being responsible for the beginning of the conversion of xylose into xylitol after 24 hours and probably for the incomplete consumption of xylose. It was observed that the xylitol yield increased progressively throughout the process, reaching a maximum value of 1.68 g of xylitol per g of xylose in 96 hours. Xylitol productivity, however, declined over time, recording values of 0.09 g/L/h in the first 24 hours and decreasing to 0.03 g/L/h at 96 hours due to the decrease in substrate. These results indicate that the green coconut husk has a significant potential for the production of xylitol, with high yield, although the productivity decreases throughout the fermentation process. This study presents a sustainable alternative for the use of an abundant agro industrial residue, contributing to the mitigation of environmental impacts and the development of high added value bioproducts.