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- 2-Fluorophenol degradation by aerobic granules in a sequencing batch reactorPublication . Duque, A. F.; Bessa, V. S.; Carvalho, M. F.; De Kreuk, M. K.; Loosdrecht, M. C. M. van; Castro, P. M. L.
- Isolation and characterization of a bacterial strain able to degrade 2-FluorophenolPublication . Duque, A. F.; Carvalho, M. F.; Janssen, D. B.; Castro, P. M. L.
- Bioaugmentation of a rotating biological contactor with a bacterial strain able to degrade fluorinated phenolsPublication . Duque, A. F.; Bessa, Vânia S.; Carvalho, M. F.; Castro, P. M. L.
- Biological treatment of a contaminated gaseous emission from a leather industry in a suspended-growth bioreactorPublication . Carvalho, M. F.; Duque, A. F.; Moura, S. C.; Amorim, Catarina L.; Ferreira Jorge, R. M.; Castro, Paula M. L.A suspended-growth bioreactor (SGB) was operated for the treatment of a gaseous stream mimicking emissions generated at a leather industrial company. The main volatile organic compounds (VOCs) present in the gaseous stream consisted of 1-methoxy-2-propanol, 2,6-dimethyl-4-heptanone, 2-butoxyethanol, toluene and butylacetate. A microbial consortium able to degrade these VOCs was successfully enriched. A laboratory- scale SGB was established and operated for 210-d with an 8 h cycle period and with shutdowns at weekends. Along this period, the SGB was exposed to organic loads (OL) between 6.5 and 2.3 £ 102 g h¡1 m¡3. Most of the compounds were not detected at the outlet of the SGB. The highest total VOC removal efficiency (RE) (ca 99%) was observed when an OL of 1.6 £ 102 g h¡1 m¡3 was fed to the SGB. The maximum total VOC elimination capacity (1.8 £ 102 g h¡1 m¡3) was achieved when the OL applied to the SGB was 2.3 £ 102 g h¡1 m¡3. For all the operating conditions, the SGB showed high levels of degradation of toluene and butylacetate (RE t 100%). This study also revealed that recirculation of the gaseous effluent improved the performance of the SGB. Overall, the SGB was shown to be robust, showing high performance after night and weekend shutdown periods.
- Degradation of fluoroanilines by the wild strain Labrys portucalensisPublication . Amorim, Catarina L.; Carvalho, Maria F.; Afonso, Carlos M. M.; Castro, Paula M. L.Aromatic amine compounds, many of them with halogenated substituents, constitute a major class of environmental pollutants that have been released into soil and water due to extensive use in industries and agriculture. Biodegradation has been found to be a major route for the removal of this kind of toxic and recalcitrant pollutants from the environment. Whereas the degradation of mono- and dichlorinated anilines has been studied, very little is known about fluorinated anilines. Therefore, the objective of this study was to investigate, under aerobic conditions, the degradation of 2-, 3- and 4-fluoroaniline by a previously isolated pure bacterium, designated as strain F11. This microorganism, identified as Labrys portucalensis, was isolated from a contaminated site in northern Portugal and has the unique capacity to utilize fluorobenzene as a sole carbon and energy source,. The results of the biodegradation of 2-, 3- and 4-fluoroaniline by strain F11 showed that this microorganism is able to completely degrade 2- fluoroaniline and partially degrade 4-fluoroaniline, when these compounds are present as a sole carbon and energy source. Biodegradation of these two compounds also occurred, although at a lower rate, in the absence of an external nitrogen source in the culture medium. To our knowledge, this is the first study reporting the biodegradation of 2- and 4-fluoroaniline as a sole carbon and energy source by a pure microbial culture. C.L. Amorim and M.F. Carvalho wish to acknowledge a research grant from Fundação para a Ciência e Tecnologia (FCT), Portugal (Ref. SFRH/BD/47109/2008 and SFRH/BPD/44670/2008, respectively) and Fundo Social Europeu (III Quadro Comunitário de Apoio). This work was supported by the FCT Project - PTDC/BIO/67306/2006
- Microbial degradation of 17β -estradiol and 17α -ethinylestradiol followed by a validated HPLC-DAD methodPublication . Ribeiro, Ana R.; Carvalho, Maria F.; Afonso, Carlos M. M.; Tiritan, Maria E.; Castro, Paula M.L.This work aimed at studying the biodegradation of two estrogens, 17agr -estradiol (E2) and 17β -ethinylestradiol (EE2), and their potential metabolism to estrone (E1) by microbial consortia. The biodegradation studies were followed by High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) using a specifically developed and validated method. Biodegradation studies of the estrogens (E2 and EE2) were carried out with activated sludge (consortium A, CA) obtained from a Wastewater Treatment Plant (WWTP) and with a microbial consortium able to degrade recalcitrant compounds, namely fluorobenzene (consortium B, CB). E2 was more extensively degraded than EE2 by CA whereas CB was only able to degrade E2. The addition of acetate as a supplementary carbon source led to a faster biodegradation of E2 and EE2. E1 was detected as a metabolite only during the degradation of E2. The 16S rRNA gene sequence analyses of strains recovered from the degrading cultures revealed the presence of the genera Pseudomonas, Chryseobacterium and Alcaligenes. The genera Pseudomonas and Chryseobacterium were retrieved from cultures supplied with E2 and EE2, while the genus Alcaligenes was found in the presence of E2, suggesting that they might be involved in the degradation of these compounds.
- Estratégias anti-microbianas na prevenção e tratamento da infecção oralPublication . Pina-Vaz, I.; Barros, J.; Noites, R.; Villa-VigiL, A.; Pintado, M.; Carvalho, M.F.A cavidade oral constitui um ecossistema propício ao desenvolvimento de biofilmes pois a variedade assinalável de superfícies da cavidade oral acomoda bactérias com tropismos diferentes. Do ponto de vista ecológico, representa um "sistema de crescimento aberto" devido à ingestão e remoção ininterrupta de microrganismos e dos seus nutrientes. Objectivo: O objectivo deste trabalho é rever a literatura existente e determinar o estado da arte sob o ponto de vista microbiológico em relação aos materiais disponíveis no tratamento das patologias periodontais e pulpar/periapicais, nomeadamente: colutórios, soluções irrigadoras, medicação intracanalar, cones de guta-percha e cimentos de obturação. Conclusão: É inquestionável as divergências dos resultados experimentais quanto à actividade antimicrobiana dos diferentes materiais, todos eles apresentam componentes antimicrobianos mas sem efeito bacteriano residual permanente. Actualmente, não há nenhum material disponível no mercado que satisfaça todos os critérios considerados ideais e com actividade antimicrobiana eficaz.
- Biodegradation of 2-fluorobenzoate and dichloromethane under simultaneous and sequential alternating pollutant feedingPublication . Osuna, M. Begoña; Sipma, Jan; Emanuelsson, Maria A. E.; Carvalho, M. Fátima; Castro, Paula M. L.Two up-flow fixed-bed reactors (UFBRs), inoculated with activated sludge and operated for 162 days,were fed 1 mmol Lˉ¹ dˉ¹ with twomodel halogenated compounds, 2-fluorobenzoate (2-FB) and dichloromethane (DCM). Expanded clay (EC) and granular activated carbon (GAC)were used as biofilm carrier. EC did not have any adsorption capacity for both model compounds tested, whereas GAC could adsorb 1.3 mmol gˉ¹ GAC for 2-FB and 4.5mmol gˉ¹ GAC for DCM. Both pollutants were degraded in both reactors under simultaneous feeding. However, biodegradation in the EC reactor was more pronounced, and re-inoculation of the GAC reactorwas required to initiate 2-FB degradation. Imposing sequential alternating pollutant (SAP) feeding caused starvation periods in the EC reactor, requiring time-consuming recovery of 2-FB biodegradation after resuming its feeding, whereas DCMdegradation recovered significantly faster. The SAP feeding did not affect performance in the GAC reactor as biodegradation of both pollutants was continuously observed during SAP feeding, indicating the absence of true starvation.
- Chryseobacterium palustre sp. nov. and Chryseobacterium humi sp. nov., isolated from industrially contaminated sedimentsPublication . Pires, Carlos; Carvalho, Maria F.; Marco, Paolo De; Magan, Naresh; Castro, Paula M. L.Two Gram-staining-negative bacterial strains, designated 3A10T and ECP37T, were isolated from sediment samples collected from an industrially contaminated site in northern Portugal. These two organisms were rod-shaped, non-motile, aerobic, catalase- and oxidase-positive and formed yellow colonies. The predominant fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C17 : 1{omega}9c and iso-C17 : 0 3-OH. The G+C content of the DNA of strains 3A10T and ECP37T was 43 and 34 mol%, respectively. The major isoprenoid quinone of the two strains was MK-6. 16S rRNA gene sequence analysis revealed that strains 3A10T and ECP37T were members of the family Flavobacteriaceae and were related phylogenetically to the genus Chryseobacterium. Strain 3A10T showed 16S rRNA gene sequence similarity values of 97.2 and 96.6 % to the type strains of Chryseobacterium antarcticum and Chryseobacterium jeonii, respectively; strain ECP37T showed 97.3 % similarity to the type strain of Chryseobacterium marinum. DNA–DNA hybridization experiments revealed levels of genomic relatedness of <70 % between strains 3A10T and ECP37T and between these two strains and the type strains of C. marinum, C. antarcticum and C. jeonii, justifying their classification as representing two novel species of the genus Chryseobacterium. The names proposed for these organisms are Chryseobacterium palustre sp. nov. (type strain 3A10T =LMG 24685T =NBRC 104928T) and Chryseobacterium humi sp. nov. (type strain ECP37T =LMG 24684T =NBRC 104927T).
- Biodegradation of 2-fluorophenol in a rotating biological contactorPublication . Duque, A. F.; Bessa, V. S.; Franco, A. R.; Carvalho, M. F.; Castro, P. M. L.