Percorrer por autor "Amorim, Catarina L."
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- 4-fluorocinnamic acid biodegradation by a rhodococcus strainPublication . Amorim, Catarina L.; Carvalho, M. F.; Afonso, C. M. M.; Castro, Paula M. L.
- Acidogenic fermentation of brewers’ spent grain monitored through two-dimensional fluorescence spectroscopyPublication . Guarda, Eliana C.; Costa, Eunice; Gil, Cátia; Amorim, Catarina L.; Galinha, Claudia F.; Duque, Anouk F.; Castro, Paula M. L.; Reis, Maria A. M.Biological systems are commonly controlled and monitored through offline and time-consuming tools, which often impairs an effective and real-time response to counteract system disturbances. The feasibility of using two-dimensional (2D) fluorescence spectroscopy as a non-invasive, non-destructive, and real-time procedure to monitor the acidogenic fermentation of brewer’s spent grain (BSG) in a granular sludge reactor was evaluated. For that, the effect of pH fluctuations on the system response was used as a model to ascertain the 2D fluorescence spectroscopy applicability to monitor the process performance, namely, to predict the fermentation products (FP) and the soluble protein (SProt) concentrations in the effluent stream through mathematical analysis. The pH fluctuations over the course of the reactor’s operation altered the granules’ microbiome composition, leading to different effluent FP profiles. Fluorescence excitation–emission matrices (EEMs) were used with projection to latent structures (PLS) modeling to predict the FP and SProt concentrations in the effluent with average errors below 0.75 and 0.43 g L–1, respectively. Both models were able to capture the tendency of the data even when the accuracy of prediction was not so high. The combined approach of using 2D fluorescence spectroscopy and mathematical analysis seemed promising for real-time monitoring of the acidogenic fermentation of complex substrates.
- Activity of nitrifying bacteria in aerobic granular sludge treating food industry wastewaterPublication . Paulo, Ana M. S.; Amorim, Catarina L.; Castro, Paula M. L.Aerobic Granular Sludge (AGS) is an innovative wastewater biological treatment, which uses less energy and space compared to other technological solutions. AGS presents a diverse microbial community responsible for the simultaneous removal of carbon and nutrients. These communities are protected by extracellular polymeric substances (EPS), which provide a compact structure to the granules. As a result, bacteria present in the aerobic granules are more resistant to variable wastewater composition, as commonly produced in food industry. In this study, carbon and NH4+ removal from a fish canning plant wastewater was evaluated using an AGS-SBR (sequential batch reactor), operated during 90 days. Chemical oxygen demand (COD) at the outlet was below the discharge limit of 125 mg O2 L-1 throughout the operation. Nitrification occurred during the first 23 days of operation. Between days 24 and 60, nitrification was completely inhibited, without ammonium removal from the wastewater. Nitrifying bacteria recovered their activity right after a decrease in the wastewater organic load, showing that the inhibition of the nitrification process was reversible. This study will contribute to our knowledge on the application of the AGS process to food industry wastewater treatment.
- Adaptative biological response of aerobic granular sludge to events of single or combined wastewater related stressorsPublication . Alves, Marta; Henriques, Isabel; Castro, Paula M. L.; Amorim, Catarina L.Wastewater comprises various stressors and their individual and combined immediate effects on aerobic granular sludge (AGS) are still underexplored. In this study, the AGS was exposed for 24 hours to wastewater with varying salt concentrations (up to 30 g NaCl L⁻¹) alongside pharmaceuticals (diclofenac, DCF or carbamazepine, CBZ). Differences in extracellular polymeric substances (EPS) production and composition were observed between single and combined stressor exposures. The removal of pharmaceuticals was influenced by the wastewater salinity level and the type of pharmaceutical, with a positive correlation found between the EPS polysaccharides content and the removal efficiency at salinity levels up to 10 g NaCl L⁻¹ . The combination of salinity and pharmaceuticals in wastewater also impacted the AGS bacteriome composition, with the bacteriome of the AGS not-exposed to stressors showing greater similarity to that of AGS exposed to DCF than to that exposed to CBZ, at each wastewater salinity level. Functional profiling suggested that short-term exposure to stressors slightly increased the relative abundance of mismatch repair, cell motility, and homologous recombination functions in the AGS microbiome. Summing up, the stressors impact on AGS bacteriome structure and EPS production varies depending on the pharmaceutical and whether it is combined with salt or not. This study unveiled the immediate AGS response to both single and combined stressors exposure, but a more thoughtful characterization of the bacteriome composition over the early adaptation period to stressors is needed to understand the community succession and to identify key microbial groups.
- Aerobic granular sludge has EPS-producing bacteria able to tolerate saltPublication . Paulo, Ana M. S.; Amorim, Catarina L.; Castro, Paula M. L.The aerobic granular sludge (AGS) process is a promising biotechnology which relies on the formation of compact biomass granules. Granulation occurs due to the overproduction of extracellular polymeric substances (EPS) by some microbes in response to stress conditions. EPS protect bacteria from the effect of toxic or inhibiting compounds present in the wastewater, such as salts. One of the current challenges is to use the AGS process to treat high salinity wastewater, commonly produced by agro-food and chemical industries. The main objective of this study was to screen for EPS-producing bacteria bacteria in an AGS reactor treating synthetic saline wastewater contaminated with a toxic compound. Several bacterial isolates were obtained from the reactor biomass. Genomic DNA was extracted and isolates (30) were grouped according to species similarity, based on RAPD profiles. Isolates displaying unique profiles (15) were subsequently identified by 16S rRNA gene sequencing analysis. Bacteria highly related to Pseudomonas, Aeromonas, Stenotrophomonas, Flavobacterium and Pseudoxanthomonas were obtained. Isolates SG4 (Stenotrophomonas) and FG10 (Flavobacterium) belong to bacterial genera associated to EPS production in granules. These were selected for growth and biofilm formation assays with increasing NaCl concentrations (0 to 35 g L-1). Both isolates were able to grow in the presence of 35 g NaCl L-1, despite at a lower growth rate. Although salt increase affected biofilm production, SG4 was the best biofilm producer. EPS production by SG4 in the presence of 10 and 20 g L-1 of NaCl was compared. EPS was extracted and the content in proteins, humic acids and carbohydrates was quantified. SG4 was able to produce more EPS in the presence of 10 g L-1 (123 mg g-1 VSS) compared to 20 g L-1 of NaCl (77.6 mg g-1 VSS). EPS-producing bacteria with ability to tolerate high salinity were retrieved from an AGS process treating synthetic wastewater. Further research is required to gain more knowledge on these bacteria and their importance for the robustness of a process treating saline wastewater.
- Aerobic granular sludge process treats real fish canning wastewater.Publication . Paulo, A. M. S.; Amorim, Catarina L.; Castro, P. M. L.Aerobic Granular Sludge (AGS) is an innovative technology used for carbon and nutrients removal from wastewater, using less space and energy compared to other biotechnological solutions. Aerobic granules present a compact structure, composed of extracellular polymeric substances (EPS), which increase AGS resistance to variable wastewater composition, as those commonly produced by industry. In this study, C, N and P-removal from a fish canning plant wastewater was evaluated using an AGS-SBR (sequential batch reactor). Throughout the first 3 months of operation with variable feed composition, the chemical oxygen demand (COD) at the outlet was below the discharge limit of 125 mg O2 L-1, phosphorous removal was stable and the nitrification process improved. At the higher organic loading rates (OLR), the AGS performance was temporary affected. This study contributes to understanding the effects of the variability of a real wastewater on an AGS process.
- Aerobic granular sludge sequencing batch reactor performance under fluorinated pharmaceuticals shock loadingsPublication . Moreira, Irina S.; Amorim, Catarina L.; Ribeiro, Ana R.; Maia, Alexandra S.; Mesquita, Raquel B. R.; Calheiros, Cristina S. C.; Rangel, António O. S. S.; Loosdrecht, Mark C. M.; Tiritan, Maria E.; Castro, Paula M. L.The widespread usage of pharmaceuticals is of increasing concern. Aerobic granular sludge sequencing batch reactors (AGS-SBR) constitute a promising technology for the treatment of wastewaters, however how the removal of carbon and nutrients can be affected by such micropollutants is largely unknown. This study evaluates the impact of different fluorinated drugs (ofloxacin, norfloxacin, ciprofloxacin and fluoxetine) on the performance of an AGS-SBR. During 468 days, a sequence of intermittent, alternating and/or continuous shock loads of pharmaceuticals were applied to an AGS-SBR and the effects on the main biological processes were evaluated. Here we report on the effect of fluoroquinolones on reactor performance. The organic removal, measured by COD, was not markedly affected by pharmaceuticals shock loads. Ammonium and nitrite were practically not detected in the bioreactor effluent indicating that the presence of the pharmaceuticals did not inhibit nitrification, whereas accumulation of nitrate in the effluent was observed, indicating that denitrification was affected. Phosphate removal was affected to some extent. There was no evidence of biodegradation whereas adsorption of the target pharmaceuticals to the AGS was observed, which were gradually released into the medium after withdrawal from the inlet stream.
- Aerobic granular sludge system under chiral pharmaceutical exposure: insights on nutrient removal performance and microbiome compositionPublication . Miranda, Catarina; Tiritan, Maria Elizabeth; Castro, Paula M. L.; Amorim, Catarina L.
- Aerobic granular sludge, a feasible technology for the treatment and recirculation of trout aquaculture water streamsPublication . Couto, Ana T.; Amorim, Catarina L.; Castro, Paula M. L.Aquaculture is one of the fastest growing food production sectors. However, land-based aquaculture faces water scarcity and space restrictions which hamper its development. Aquaculture recirculation systems (RAS) help tackle these problems, although in most systems the recycling of water increases nutrient and organic matter concentrations, which often translates to fish mortality. This work aimed to evaluate the feasibility of an aerobic granular sludge (AGS) system as a novel alternative for the treatment of aquaculture streams, characterized by low nutrient and carbon concentrations. The efficiency for nutrients removal aiming at water recirculation was assessed as well as the AGS microbiome composition dynamics over operation. The AGS system was inoculated with mature granules from a full-scale WWTP and fed with a synthetic medium mimicking a trout farm aquaculture recycling water. High ammonium removal efficiencies of 87-100% and ammonium removal rate of approximately 14.5 mg NH4+-N/(L⋅d) were achieved. The AGS microbiome, mainly composed by members of the Proteobateria phylum, had a core microbiome composed of different functional groups (e.g. denitrifying bacteria, nitrogen fixing bacteria, ammonium oxidizing bacteria, phosphorus accumulating bacteria and extracellular polymeric substance (EPS) producing bacteria). The AGS system was able to produce effluents of high-quality, with ammonium content below the toxic levels for fish, and thus suitable for recirculating in the aquaculture.
- Aerobic granular sludge, a feasible technology for the treatment and recirculation of trout aquaculture water streamsPublication . Couto, Ana T.; Amorim, Catarina L.; Castro, Paula M. L.