Evaluación de la degradación químico – biológica de una solución modelo de cafeína

Abstract

The present work was based on the evaluation of the chemical-biological degradation of a caffeine model solution (50 ppm), for this, it was first proposed to carry out a chemical degradation through caffeine photocatalysis with TiO2 as a photocatalyst, then a biological degradation test was carried out, for this a strain of caffeine-degrading bacteria obtained from a coffee crop and finally a combined trial was performed in sequence. In the chemical part, a maximum degradation of 88 ± 2 % was obtained, after three hours of exposure to a pH = 4 and with the presence of H2O2 in a 2 to 1 ratio with the photocatalyst. For the biological degradation, a maximum degradation of 87 ± 2 % was obtained, after 48 hours of degradation at 150 rpm and 35 ºC. The bacteria used were Pseudomonas sp identified through their morphology and biochemical tests. Regarding the combined degradation, a degradation percentage of 99 ± 1 % was obtained, but cannot be attributed to sequential degradation because the same degradation is triggered in the control solution after the study time (24 hours), this may be due to the presence of phototoxic products in the solution.