RESUMEN
This study evaluated the influence of carbon sources on alginate-like exopolymers (ALE) and tryptophan (Trp) biosynthesis in the aerobic granular sludge (AGS). With acetate, the highest biopolymers levels, per gram of volatile suspended solids (VSS) (418.7 mgALEâg-1 and 4.1 mgTrpâgVSS-1), were found likely due to biomass loss throughout the operation, which resulted in lower sludge age (4-7 days) and shorter famine period. During granulation, encouraging results on ALE production were obtained with propionate (>250 mgALEâgVSS-1), significantly higher than those found with glycerol, glucose, and sucrose. Regarding tryptophan production, propionate and glycerol proved to be good substrates, although the content was still lower than acetate (1.6 mgTrpâgVSS-1). Granules fed with glucose showed the worst results compared to the other substrates (38.5 mgALEâVSS-1 and 0.6 mgTrpâgVSS-1) due to the filamentous microorganisms' abundance found. Therefore, this study provides insights to value the production of compounds of industrial interest in AGS systems.
Asunto(s)
Aguas del Alcantarillado , Aguas Residuales , Aerobiosis , Alginatos , Reactores Biológicos , Carbono , Glucosa , Glicerol , Propionatos , Aguas del Alcantarillado/química , Triptófano , Eliminación de Residuos Líquidos/métodosRESUMEN
This work assessed the effect of the antibiotics trimethoprim (TMP) and sulfamethoxazole (SMX) on the granulation process, microbiology, and organic matter and nutrient removal of an aerobic granular sludge (AGS) system. In addition, after the maturation stage, the impact of the redox mediator anthraquinone-2,6-disulfonate (AQDS) (25 µM) on the biotransformation of the antibiotics was evaluated. The reactor R1 was maintained as a control, and the reactor R2 was supplemented with TMP and SMX (200 µg L-1). The ability to remove C, N, and P was similar between the reactors. However, the structural integrity of the AGS was impaired by the antibiotics. Low TMP (â¼30%) and SMX (â¼60%) removals were achieved when compared to anaerobic or floccular biomass aerobic systems. However, when the system was supplemented with AQDS, an increase in the removal of TMP (â¼75%) and SMX (â¼95%) was observed, possibly due to the catalytic action of the redox mediator on cometabolic processes. Regarding the microbial groups, whereas Proteobacteria and Bacterioidetes increased, Planctomycetes decreased in both reactors. However, TMP and SMX presence seemed to inhibit or favor some genera during the formation of the granules, possibly due to their bactericidal action.