Browsing by Author "Castro, Paula Maria Lima"
Now showing 1 - 10 of 13
Results Per Page
Sort Options
- 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.
- Biodegradation of 2,4 DCP herbicide by streptomyces collinus isolated from wastewater treatment plant in eastern AlgeriaPublication . Oumeima, Boufercha; Allaoueddine, Boudemagh; Moreira, Irina Sousa; Castro, Paula Maria LimaWastewater treatment plants are the place where most pollutants are transported. 2, 4 DCP is an herbicide widely used in agriculture. This carcinogenic pollutant is very dangerous because it can reach surface waters through runoff and deep waters widely used by humans and animals. Water treatment plants are a reservoir of multiple and varied microorganisms, able to eliminate the toxic effect of many pollutants. The actinobacteria by their impressive metabolic abilities, are among the most appreciated microbial agents in the bioremediation of these hydric sites. In order to evaluate the functionality of the Ibn Ziad station in Constantine, we tested some physicochemical characteristics and the biodiversity of actinobacteria able to tolerate and degrade 2, 4 DCP. Sampling was carried out on raw wastewater, treated water and aeration tank water. The parameters studied were temperature, pH, conductivity, salinity, BOD5, DOC and suspended matters (MES). Actinobacteria were isolated on four selective media, namely AF, modified Czapeck dox, ISP4, Olson. The determination of herbicide biodegradation capacity by these bacteria was tested first on a minimum solid medium supplemented with 50 mg/L of 2, 4-DCP as a single carbon and energy source. Isolates that grew on this medium were cultured in liquid medium in the presence of 50 mg/L of the same pollutant. The degradation kinetics were monitored by HPLC. The best performing isolate was identified by phenotypic and molecular methods. The results show slightly alkaline pH, ambient temperatures. The DOC/BOD5 ratio is less than three, which indicates a slightly biodegradable effluent. While the MES concentration is around 256.7 mg/L. This station shows an important biodiversity of actinobacteria, with 25 isolates, among which 18 are able to live in the presence of 2, 4-DCP. The study of the kinetics of growth and degradation shows a good performance of an isolate, with a degradation rate of 45% after one month of incubation. The polyphasic identification of this bacterium, allows to assign it to the species Streptomyces collinus strain NBRC 12759 16S. These results show that the waters of thisstation are rich in actinobacteria able to degrade the herbicide 2, 4-DCP. These bacteria can be used in the bioremediation of water ecosystems polluted by this phytosanitary product
- Biodegradation of 2,4 DCP herbicide by streptomyces collinus isolated from wastewater treatment plant in eastern AlgeriaPublication . Oumeima, Boufercha; Allaoueddine, Boudemagh; Moreira, Irina Sousa; Castro, Paula Maria Lima
- Efficient ammonium removal from marine aquaculture wastewater with microalgal-bacterial granular sludge technologyPublication . Alves, Marta; Oliveira, Ana Sofia; Castro, Paula Maria Lima; Amorim, Catarina LeiteWater recirculation in marine aquaculture is fundamental for the protection of water resources and for the sector sustainability as it enables to reduce water usage 1. Microalgal-bacterial granular sludge (MBGS) has the potential to increase the removal efficiency of pollutants from wastewaters benefiting from the diverse metabolism allowing water recirculation. Moreover, MBGS would allow costs reduction both in biomass separation from the treated water given the rapid settling properties and in aeration due to microalgae oxygen production 2.This study aimed to develop MBGS able to treat marine aquaculture effluents. For that, a lab-scale photo sequencing batch reactor was inoculated with activated sludge, previously adapted to salty wastewater, and a microalgae consortium enriched from water collected at a marine aquaculture. Feeding composition was established to simulate marine aquaculture streams. The aggregation of microalgal and bacterial biomass to form granular structures occurred rapidly. Throughout the operation, dark green granules with a dense and compact structure became predominant together with an increase in chlorophyll and carotenoids content in biomass. Ammonia was absent from the reactor effluent, but the nitrite levels were often above the toxicity levels for fish. Nevertheless, the dissolved oxygen concentration in the treated water was high (> 8.63 mg/L). The microalgal-bacterial granules proved to be efficient in producing streams with high dissolved oxygen levels, lowering the needed of water oxygenation before reuse and without ammonium ions. However, for water recirculation, improvement of the nitrite removal is needed to maintain the levels below the fish toxicity levels.
- 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
- Isolation and identification of actinomycetes degrading the fungicid Allial from the activated sludge of the wastewater treatment plant Ibn Ziad (Constantine city)Publication . Oumeima, Boufercha; Moreira, Irina Sousa; Castro, Paula Maria Lima; Allaoueddine, BoudemaghThe old methods of agriculture were based on the use of intensive manual labor. The twentieth century saw the birth of a revolution in agricultural practices, which relied mainly on plant protection techniques. These new perspectives have paved the way for an agriculture dominated by pesticides. The use of these molecules has improved yields and crop diversity to meet the nutritional needs of the growing world population. However, in recent years, other health and environmental problems have arisen due to uncontrolled overuse. Allial (fosetyl aluminum) is a systemic fungicide of the phosphonate class. It is not very persistent in soils and water and is recalcitrant to hydrolysis at environmental pH. This fungicide is also very soluble in water and can therefore reach surface waters by leaching from agricultural soils. Photolysis of this xenobiotic is not possible. In order to remove this fungicide from wastewater, biological treatment methods are necessary. Activated sludge microorganisms can play an important role in its biodegradation. In this study, were isolated actinomycetes from activated sludge of the wastewater treatment plant of Ibn Ziad. These bacteria, known by their extraordinary metabolic diversities, were tested for their aptitudes to degrade this toxic pesticide. Minimum salt medium supplemented with different concentrations up to 200 mg/L of fosetyl aluminum as the only carbon source. The cultures were incubated during 5 days at a temperature of 30° C. According to the results obtained, five isolates of actinobacteria showed a significant potential for the biodegradation of this fungicide. The identification of these isolates by analysis of the 16S rDNA gene allowed to assign them to the Streptomyces genus.
- 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.
- Occurrence of fecal bacteria and zoonotic pathogens in different water bodies: supporting water quality managementPublication . Ferreira, Vânia; Magalhães, Rui; Teixeira, Paula; Castro, Paula Maria Lima; Calheiros, Cristina Sousa CoutinhoWater contaminated with microbiological and chemical constituents can cause a variety of diseases. Water bodies may become contaminated by wild and domestic animal feces, agricultural runoff or sewage, and are often overlooked as a reservoir and source of human infection by pathogenic microorganisms. The objectives of this study were to evaluate the presence of the zoonotic pathogens, Salmonella spp. and Listeria monocytogenes, in various water bodies located in urban and rural areas in the north of Portugal. Water samples were collected from six sites, including natural and artificial ponds, in two different time periods. Several water quality physicochemical parameters, as well as fecal indicator bacteria, were evaluated. High levels of total coliforms (>1.78 log CFU/100 mL) were detected in all samples, and substantial numbers of Enterococcus (>2.32 log CFU/100 mL) were detected in two ponds located in a city park and in an urban garden. Escherichia coli counts ranged from undetectable to 2.76 log CFU/100 mL. Salmonella spp. was isolated from two sites, the city park and the natural pond, while L. monocytogenes was isolated from three sites: the city garden, the natural pond and the artificial pond, both in the rural area. These data show that artificial and natural ponds are a reservoir of fecal indicator bacteria and enteric and zoonotic pathogens. This may impact the potential risks of human infections by potential contaminants during recreational activities, being important for assessing the water quality for strategic management of these areas.
- Study of the biodegradation of the insecticide thiamethoxam by streptomyces strains isolated from wastewater treatment plants in AlgeriaPublication . Boufercha, Oumeima; Moreira, Irina Sousa; Castro, Paula Maria Lima; Allaoueddine, BoudemaghThiamethoxam is a neonicotinoid insecticide used to control a wide range of pests in a broad variety of agricultural fields. Thiamethoxam may pose some risk to the environment and the health of living organisms. The objective of this study is to isolate actinomycetes strains able to degrade thiamethoxam. In the present study, three thiamethoxam-degrading actinomycetes, were isolated from the activated sludge of Oued El Athmania wastewater treatment plant (Algeria). On the basis of morphological, physiological and biochemical characteristics, combined with phylogenetic analysis of the 16S rRNA gene, these actinomycetes were affiliated to the genus Streptomyces. Evaluation of the degradation of 35 mg/L of thiamethoxam was accomplished in liquid medium. The monitoring of the biodegradation was done by HPLC. The results show that Streptomyces sp. OV was able to degrade 84% of thiamethoxam in the presence of 10 mM glucose, while the strains Streptomyces sp. OB and Streptomyces sp. OH could degrade 78% and 69% of thiamethoxam, respectively, in the presence of 5.9 mM sodium acetate, during 18 days of incubation. Experiments were performed at 30°C, pH 7 and under agitation of 130 rpm. The isolated Streptomyces strains are potential candidates to be used for the developed of biotechnological solutions to eliminate this insecticide from contaminated sites.
- Study of the biodegradation of the insecticide alpha-cypemethrin by indigenous actinobacteria isolated from activated sludgePublication . Boufercha, Oumeima; Moreira, Irina Sousa; Castro, Paula Maria Lima; Boudemagh, Allaoueddine