Browsing by Author "Pereira, Sofia Isabel Almeida"
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- Assessment of culturable bacterial endophytic communities colonizing Canna flaccida inhabiting a wastewater treatment constructed wetlandPublication . Calheiros, Cristina Sousa Coutinho; Pereira, Sofia Isabel Almeida; Brix, Hans; Rangel, Antonio Osmaro Santos Silva; Castro, Paula Maria LimaMicroorganisms, including the bacterial populations living inside plant tissues (endophytes), and vegetation are components of constructed wetland (CW) systems playing pivotal roles in the water treatment process and in the ecosystem establishment. The present study focuses on the assessment of the culturable endophytic bacterial communities of Canna flaccida plants, the dominant plant species in a polycultured CW treating wastewater from a tourism facility. Bacterial endophytes were grouped by random amplified polymorphic DNA and identified by 16S ribosomal RNA gene sequencing. From the bacterial isolates, 103 were considered for phylogenetic analysis, falling in 25 genera within the γ-, β-, α-Proteobacteria, Flavobacteria, Sphingobacteria, Actinobacteria and Bacilli classes. Forty-nine percent of the isolates belonged to the Enterobacteriaceae family, suggesting that the plants in CW systems may act as a sink of potential human pathogenic microorganisms; nevertheless their abundance on the plant tissues was reduced from the inlet (62%) to the outlet zone (38%). High diversity in terms of genera was found in C. flaccida tissues, although the number of genera common to both sampling zones was low, which suggests that the processes occurring within the CW, including the water characteristics gradient from the inlet to the outlet (e.g. total suspended solids, organics and fecal loads), had the ability to shape the diversity of the endophytic communities.
- Bacteria immobilsation on hydroxyapatite surface for wastewater treatmentPublication . Pereira, Sofia Isabel Almeida; Piccirillo, Clara; Marques, Ana P. G. C.; Pullar, Robbert C.; Pintado, Manuela M. E.; Castro, Paula M. L.Heavy metals pollution in the environment is a big cause of concern, due to the toxicity of the metals themselves. In this work we propose an innovative method for heavy metals removal from contaminated waste water – a combination of hydroxyapatite (already used for water treatment) and microorganisms. Selected bacterial strains were immobilised on the surface of hydroxyapatite of natural origin (extracted from cod fish bones). These systems were used to tested on heavy metals, such as zinc and cadmium, from water solutions. The three strains used were Pseudomonas fluorescens, Microbacterium oxydans and Cupravidus sp.; they were selected as they showed high heavy metal resistance. SEM micrographies were used to study their immobilization on the hydroxyapatite surface. Solutions containing different concentrations of either Zn (II), Cd (II) or both metals at the same time were used. Results showed that the combination of hydroxyapatite and bacteria increases the metal uptake, indicating a synergistic action between the solid support and the bacteria biofilm. Particularly high removal rates were observed for higher heavy metal concentrations and for the Pseudomonas fluorescens strain. This work shows a promising way for environmental remediation, combining products of natural origin with microbiology.
- Improving soil macro- and meso-fauna diversity of Mediterranean agrosystems: application to maize crops and vineyardsPublication . Delcourt, Ninon; Pereira, Sofia Isabel Almeida; Moreira, Helena; Castro, Paula Maria Lima; Prieto-Fernández, Angeles; Epelde, Lur; Cortet, Jérôme
- Microbial inoculants alleviate the adverse effects of Cu-contaminated soils amended with biochar on sunflower growthPublication . Godinho, Mariana; Moreira, Helena; Castro, Paula Maria Lima; Pereira, Sofia Isabel AlmeidaSoil contamination is a pressing global issue driven by various anthropogenic activities, such as mining. This study evaluated the use of biochar and microbial inoculants as phytoremediation allies in promoting sunflower growth in a Cu-contaminated mining soil. Sunflower seedlings were planted in a Cu-contaminated mining soil amended with increasing doses of biochar (0 %, 2.5 %, and 5 % w/w) under greenhouse conditions. Seedlings were singly and co-inoculated with the bacterial strain Pseudomonas reactans EDP28 and the commercial arbuscular mycorrhizal fungi (AMF) Rhizophagus irregularis. The addition of 2.5 and 5 % of biochar to the Cu-contaminated mining soil significantly reduced sunflower shoot biomass by 49 % and 46 %, respectively, and root biomass by 63 and 50 %, respectively. This decrease is likely attributed to increased Cu accumulation in plant tissues, particularly in the roots (on average +38 %), driven by the enhanced availability of Cu in the soil. However, microbial inoculation, particularly the combined application of the bacterial strain and the AMF (Mix treatment), significantly supported sunflower growth and resilience under metal stress conditions. Mix treatment improved root elongation, root biomass, and shoot biomass by 48 %, 143 %, and 122 % at 2.5 % biochar, and by 45 %, 54 %, and 137 % at 5 % biochar, respectively. This was achieved by improving chlorophyll content and nutrient use efficiency. The beneficial effects were clearer in soils without biochar addition, where inoculation fully promoted sunflower growth. In contrast, in biochar-amended soils, inoculation helped to partially counteract the negative effects of biochar on plant development. This study demonstrates that sunflowers can effectively tolerate and accumulate high levels of Cu in their tissues, making them a promising candidate for phytoremediation strategies in mining areas, especially when aided by microbial inoculants, whilst the role of biochar in phytoremediation requires further investigation. Biochar can facilitate metal accumulation, but its impact on plant growth needs careful management. Future research should focus on optimizing the application rates and combinations of biochar and microbial inoculants to maximize phytoremediation efficiency and minimize any adverse effects on plant growth.
- Screening of growth promotional traits of five metal resistant pgpr – possible uses for phytoattenuation of zn and cd contaminated landPublication . Moreira, Helena Maria Gomes; Pereira, Sofia Isabel Almeida; Marques, Ana P. G. C.; Rangel, António O.S.S.; Castro, Paula M. L.