Evaluación de la eficiencia del ácido acético extraído del mucilago de cacao para su uso como desinfectante.

Abstract

The objective of this work is to evaluate the efficiency of acetic acid in inhibiting the growth of two pathogenic microorganisms (E. coli and Trichoderma spp) through the application of the contact plate method; acetic acid was obtained from an alcoholic-acetic fermentation of cocoa mucilage which was concentrated through a liquid-liquid distillation process coupled to vacuum. Four different concentrations of yeast (Saccharomyces cerevisiae) were defined for the alcoholic fermentation of two liters of exudate, which were: white, 1 g/L, 2 g/L and 3 g/L; during 7 days to check which one has better characteristics. While acetic fermentation was developed with 250 ml of acetobacteria at a fixed concentration after 3 days. Better physicochemical characteristics were obtained in the sample with 3 g/L of yeast with a total acidity of 2.54%, a pH of 4.5 and a concentration of 18.88 mg/L of polyphenols.After fermentation, a filtration was made with a cloth to eliminate biomass, from this filtered solution a volume of 1 liter of each sample was taken and packed in different labeled amber flasks, consequently the liquid-liquid distillation was made in a rotavapor coupled to a vacuum pump, at a temperature of 100°C and 90 rpm for a time interval of 25 minutes where a higher yield was achieved in the sample with a concentration of yeast of 3 g/L with a recovery percentage of 31.3%. To carry out the plate method, 4 assays were performed for each yeast concentration added, corresponding to: blank, 1 g/L, 2 g/L and 3 g/L; of which the method was performed in 4 volumes of acetic acid, which were a blank, 1 ml, 2 ml and 3 ml; they were performed in triplicate of each volume, giving a total of 12 assays for each sample of different concentration of yeast applied to the two strains separately. E. coli ATCC 25922 was grown at 35°C for 3 days while Trichoderma spp was grown at 30°C for 3 days. The results proved that, when increasing the concentration of acetic acid, it presents a greater efficiency in inhibition due to the fact that the results showed a reduction with the acid obtained from 3 g/L of yeast applied with a volume of 3ml in triplicate from 164 CFU/ml to 10 CFU/ml of the strain of E. coli ATCC 25922 and at par with Trichoderma spp that went from 4 CFU/ml to 0 CFU/ml. This evaluation proves that the acetic acid obtained has a high potential as a disinfectant due to its high capacity to inhibit microbial load, thus enhancing the alternatives to obtain benefits from agroindustrial waste generated in the cocoa sector, thus presenting an environmentally friendly commercial alternative.