Browsing by Author "Castro, Paula M.L."
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- Arsenic, lead and nickel accumulation in Rubus ulmifolius growing in contaminated soil in PortugalPublication . Marques, Ana P. G. C.; Moreira, Helena; Rangel, António O.S.S.; Castro, Paula M.L.This work investigates the potential of Rubus ulmifolius, indigenous to ametal contaminated site – Esteiro de Estarreja – for phytoremediation purposes. The site has a long history of metal contamination. The accumulation of lead (Pb), arsenic (As) and nickel (Ni) in different sections – roots, stems and leaves – of the plant was assessed and compared to the levels of those metals in the soil and in the available fraction. The distribution of metals throughout the area was quite heterogeneous, presenting levels of As, Pb and Ni of up to 3078, 1400 and 135mg kg¯¹, respectively, and the metal content in the sections of R. ulmifolius collected in the banks of the stream varied among sites of collection. Levels of metals were higher in the plant roots: As levels (mg kg¯¹) ranged from 277 to 1721 in the roots, 30 to 110 in the stems, and 60 to 265 in the leaves; Pb concentrations (mg kg¯¹) ranged from 248 to 1178 in the roots, 35 to 133 in the stems, and 25 to 149 in the leaves; and Ni (mg kg¯¹) ranged from 48 to 151 in the roots. Significant correlations were found between the total levels of Pb and As in the soil and the levels in the roots of the plant; further correlations between total and available levels in the soil and metals in other plant tissues were generally found as non-significant. According to the metal accumulation patterns of R. ulmifolius, this species seems to be valuable for application in phytostabilisation strategies.
- Bacterial community and system performance of an aerobic granular sludge reactor treating pharmaceutical wastewaterPublication . Amorim, Catarina L.; Moreira, Irina S.; Ribeiro, Ana R.; Tiritan, Maria E.; Henriques, Isabel S.; Castro, Paula M.L.Pharmaceuticals often reach wastewater treatment systems where low removal rates are observed. In the present study the potential impact of a mixture of such micro-pollutants on an aerobic granular sludge-sequencing batch reactor (AGS-SBR) was investigated using a lab-scale bioreactor. COD and P- removals were affected due to the load of pharmaceuticals resulting in a decrease of the COD uptake and the P-release during the anaerobic feeding phase, but the discharge limits were not exceeded. Nevertheless, both processes returned to its normal operation after resuming the pharmaceuticals feeding. The nitrification process was also affected but the activity of bacteria responsible for both nitrification steps was able to recover. The exposure to the pharmaceuticals induced alterations in the bacterial community structure.
- Biodegradation of diclofenac by the bacterial strain labrys portucalensis Fl 1Publication . Moreira, Irina S.; Bessa, Vânia S.; Murgolo, Sapia; Piccirillo, Clara; Mascolo, Giuseppe; Castro, Paula M.L.Diclofenac (DCF) is a widely used non-steroidal anti-inflammatory pharmaceutical which is detected in the environment at concentrations which can pose a threat to living organisms. In this study, biodegradation of DCF was assessed using the bacterial strain Labrys portucalensis F11. Biotransformation of 70% of DCF (1.7–34 μM), supplied as the sole carbon source, was achieved in 30 days. Complete degradation was reached via co-metabolism with acetate, over a period of 6 days for 1.7 µM and 25 days for 34 μM of DCF. The detection and identification of biodegradation intermediates was performed by UPLC-QTOF/MS/MS. The chemical structure of 12 metabolites is proposed. DCF degradation by strain F11 proceeds mainly by hydroxylation reactions; the formation of benzoquinone imine species seems to be a central step in the degradation pathway. Moreover, this is the first report that identified conjugated metabolites, resulting from sulfation reactions of DCF by bacteria. Stoichiometric liberation of chlorine and no detection of metabolites at the end of the experiments are strong indications of complete degradation of DCF by strain F11. To the best of our knowledge this is the first report that points to complete degradation of DCF by a single bacterial strain isolated from the environment.
- Biodegradation of p-chlorophenol by a microalgae consortiumPublication . Lima, Sofia A. C.; Raposo, M. F.; Castro, Paula M.L.; Morais, R. M. S. C.An aquatic communitywas recovered from a waste discharge container fed with several aromatic pollutants. After 3 months of selective enrichment with p-chlorophenol and p-nitrophenol, two microalgae species, Chlorella vulgaris and Coenochloris pyrenoidosa, were recovered from the microbial consortium. As an axenic culture, this microalgae consortium was able to remove p-chlorophenol under different photo-regimes. Cultures grown under a 24 h light regime were capable of biodegrading 50mg l 1 of p-chlorophenol within 5 days. Addition of zeolite, an adsorbing material, did not improve the p-chlorophenol removal. However, when p-chlorophenol at 150mg l 1 was fed to the culture supplemented with zeolite, the growth rate of the consortium improved, but the lag phase was longer (16 against 14 days in the absence of zeolite).
- Biodegradation potential of the soil bacterial community from a polluted site in the northern of PortugalPublication . Moreira, Irina S.; van Acker, J.; Amorim, Catarina L.; Castro, Paula M.L.
- Biological treatment of a contaminated gaseous emission from a paint and varnish plant—from laboratory studies to pilot-scale operationPublication . Bastos, Filipe S.C.; Castro, Paula M.L.; Jorge, Ruben FerreiraA Vapour-Phase Bioreactor (VPB), namely a biotrickling filter, was scaled-up and operated in-situ for the treatment of gaseous emissions from a paint and varnish industrial plant. A microbial culture able to degrade the target compounds was enriched and a laboratory-scale VPB was established in order to evaluate the treatment's performance. The VPB presented removal efficiencies higher than 90% when exposed to Organic Loads (OL) of ca 50 g h−1 m−3 of reactor. The VPB was exposed to dynamic conditions often found in-situ (eg night and weekend shutdown periods) and showed a fast capacity to recover, with and without mineral medium recirculation. After a prolonged interruption period (10 months), the VPB was not able to cope with OL of ca 25 g h−1 m−3 of reactor and re-inoculation was required in order to recover the treatment performance. The VPB also showed limited treatment when exposed to higher OL (ca 500 g h−1 m−3 of reactor). The VPB was then scaled-up and a 3 m3 VPB was operated in-situ, showing removal efficiencies higher than 50% when exposed to an OL of c 5 g h−1 m−3 of reactor, thus complying with current legal demands. The addition of a maintenance feed was shown to be a useful tool for VPB pilot-scale operation when shutdown periods occurred. A factorial design of experiments was carried out, which allowed reduction to one-tenth of the initial supply of the main mineral medium constituents, namely phosphate buffer, ammonium and magnesium salts, and also elimination of the metal supplement. Overall, the VPBs were shown to be robust equipment, being able to respond actively to dynamic treatment scenarios, particularly night and weekend shutdown periods. Copyright © 2003 Society of Chemical Industry
- Bioprospecting microalgae for treatment of marine aquaculture wastewaterPublication . Alves, Marta; Cardador, Martim; Castro, Paula M.L.; Amorim, Catarina L.
- Changes in the bacterial community structure in two-stage constructed wetlands with different plants for industrial wastewater treatmentPublication . Calheiros, Cristina S.C.; Duque, Anouk F.; Moura, Alexandra; Henriques, Isabel S.; Correia, António; Rangel, António O.S.S.; Castro, Paula M.L.This study focused on the diversity of bacterial communities from two series of two-stage constructed wetlands (CWs) treating tannery wastewater, under different hydraulic conditions. Series were separately planted with Typha latifolia and Phragmites australis in expanded clay aggregates and operated for 31 months. The effect of plant species, hydraulic loading and unit stage on bacterial communities was addressed through bacterial enumeration and denaturating gradient gel electrophoresis (DGGE). Diverse and distinct bacterial communities were found in each system unit, which was related in part to the type of plant and stage position (first or second unit in the series). Numerical analysis of DGGE profiles showed high diversity in each unit with an even distribution of species. No clear relation was established between the sample collection time, hydraulic loading applied and the bacterial diversity. Isolates retrieved from plant roots and substrates of CWs were affiliated with c-Proteobacteria, Firmicutes, a-Proteobacteria, Sphingobacteria, Actinobacteria and Bacteroidetes. Both series were effective in removing organic matter from the inlet wastewater, however, based on batch degradation experiments it seems that biodegradation was limited by the recalcitrant properties of the wastewater
- Chiral HPLC-FD method validation for determination of several Beta-Blockers and Fluoxetine in biodegradation assaysPublication . Ribeiro, Ana R.; Castro, Paula M.L.; Afonso, Carlos; Tiritan, Maria E.Chiral pharmaceuticals and the fate and effects of their enantiomers in the environment are still largely unknown [1, 2]. Enantiomers have different interactions with enzymes, receptors and any chiral molecules leading to different biological activities and affecting organisms in a different manner. Thus, biodegradation tends to be enantioselective in contrast to abiotic degradation. The methods developed to quantify the enantiomeric fraction in the environment and to follow biodegradation are scarce [3]. Thus in this work we describe the development and validation of HPLC methods that allow the enantiomeric separation of widely used drugs namely four beta-blockers: alprenolol (ALP), propranolol (PHO), metoprolol (MET) and atenolol (ATE) and the antidepressant fluoxetine (FX). The macrocyclic antibiotic vancomycin CSP (ASTEC Chirobiotic V 5µm) was used under polar organic mode (methanol:ethanol:triethylamine:acetic acid.50:50 v/v) and fluorescence detection for enantiomeric fraction quantification. The developed methods were established using a minimal medium inoculated with activated sludge as a matrix which is the condition used in the biodegradation studies. The vancomycin CSP was able to resolve ALP and PHO as well as MET, ATE and FX in two chromatographic runs. The chromatographic parameters obtained have shown the separation factor (α) between 1.12 and 1.34 and resolution (Rs) between 1.30 and 4.35. The methods demonstrated to be selective and linearity with r2 higher than 0,999 for the range selected. The method detection limits were between 2.5 to 10ng/mL. These methods were applied to follow the biodegradation of the target chiral compounds during 15 days. The biodegradation assays were performed using activated sludge from a WWTP and the results indicate the higher degradation extents for the S- enantiomer forms.
- Co-metabolic degradation of chlorobenzene by the fluorobenzene degrading wild strain Labrys portucalensisPublication . Moreira, Irina S.; Amorim, Catarina L.; Carvalho, Maria F.; Castro, Paula M.L.Due to the widespread use of chlorobenzene (CB), environmental contamination with this compound is a major concern. A previously isolated bacterium named Labrys portucalensis (strain F11), that is able to use fluorobenzene (FB) as sole carbon and energy source, was tested for its capability to degrade CB. Strain F11 was able to partially degrade CB only when F11 cells were previously grown in FB. Biodegradation of 0.5 mM of CB was achieved at a rate of 7.95 0.39 mmol l 1 day 1 with concomitant stoichiometric release of 50% of the chloride, while degradation of 1 mM of this compound resulted in 85% degradation at a rate of 16.9 0.81 mmol l 1 day 1 and with a 15% chloride release on the basis of the amount of compound biodegraded. Total CB biodegradation and dechlorination was only achieved when FB was also supplied to F11 cultures, suggesting cometabolic transformation. Total degradation of 0.5 mM of CB and 0.5 mM of FB occurred simultaneously at degradation rates of 105 6.07 mmol l 1 day 1 and 126 16.2 mmol l 1 day 1 respectively, with stoichiometric halogen release. Growth yield was lower when both substrates were present, suggesting synergistic inhibition. To our knowledge, this is the first time that co-metabolic biodegradation of CB in the presence of the fluorinated analogue is reported.