Microalgae-Based Remediation of Real Textile Wastewater: Assessing Pollutant Removal and Biomass Valorisation.

The textile industry generates highly contaminated wastewater. It severely threatens local ecosystems without proper treatment, significantly diminishing biodiversity near the discharge point. With rapid growth rates, microalgae offer an effective solution to mitigate the environmental impact of textile wastewater, and the generated biomass can be valorised. This study sets out to achieve two primary objectives: (i) to assess the removal of pollutants by Chlorella vulgaris from two distinct real textile wastewaters (without dilution) and (ii) to evaluate microalgal biomass composition for further valorisation (in a circular economy approach). Microalgae grew successfully with growth rates ranging from 0.234 ± 0.005 to 0.290 ± 0.003 d-1 and average productivities ranging from 78 ± 3 to 112.39 ± 0.07 mgDW L-1 d-1. All cultures demonstrated a significant reduction in nutrient concentrations for values below the legal limits for discharge, except for COD in effluent 2. Furthermore, the pigment concentration in the culture increased during textile effluent treatment, presenting a distinct advantage over conventional ones due to the economic value of produced biomass and pigments. This study underscores the promise of microalgae in textile wastewater treatment and provides valuable insights into their role in addressing the environmental challenges the textile industry poses.

International Care programs for Pediatric Post-COVID Condition (Long COVID) and the way forward.

BACKGROUND: Pediatric Post-COVID-Condition (PPCC) clinics treat children despite limited scientific substantiation. By exploring real-life management of children diagnosed with PPCC, the International Post-COVID-Condition in Children Collaboration (IP4C) aimed to provide guidance for future PPCC care. METHODS: We performed a cross-sectional international, multicenter study on used PPCC definitions; the organization of PPCC care programs and patients characteristics. We compared aggregated data from PPCC cohorts and identified priorities to improve PPCC care. RESULTS: Ten PPCC care programs and six COVID-19 follow-up research cohorts participated. Aggregated data from 584 PPCC patients was analyzed. The most common symptoms included fatigue (71%), headache (55%), concentration difficulties (53%), and brain fog (48%). Severe limitations in daily life were reported in 31% of patients. Most PPCC care programs organized in-person visits with multidisciplinary teams. Diagnostic testing for respiratory and cardiac morbidity was most frequently performed and seldom abnormal. Treatment was often limited to physical therapy and psychological support. CONCLUSIONS: We found substantial heterogeneity in both the diagnostics and management of PPCC, possibly explained by scarce scientific evidence and lack of standardized care. We present a list of components which future guidelines should address, and outline priorities concerning PPCC care pathways, research and international collaboration. IMPACT: Pediatric Post-COVID Condition (PPCC) Care programs have been initiated in many countries. Children with PPCC in different countries are affected by similar symptoms, limiting many to participate in daily life. There is substantial heterogeneity in diagnostic testing. Access to specific diagnostic tests is required to identify some long-term COVID-19 sequelae. Treatments provided were limited to physical therapy and psychological support. This study emphasizes the need for evidence-based diagnostics and treatment of PPCC. The International Post-COVID Collaboration for Children (IP4C) provides guidance for guideline development and introduces a framework of priorities for PPCC care and research, to improve PPCC outcomes.

Comparative assessment of microalgal growth kinetic models based on light intensity and biomass concentration.

The comprehensive evaluation and validation of mathematical models for microalgal growth dynamics are essential for improving cultivation efficiency and optimising photobioreactor design. A considerable gap in comprehending the relation between microalgal growth, light intensity and biomass concentration arises since many studies focus solely on associating one of these factors. This paper compares microalgal growth kinetic models, specifically focusing on the combined impact of light intensity and biomass concentration. Considering a dataset (experimental results and literature values) concerning Chlorella vulgaris, nine kinetic models were assessed. Bannister and Grima models presented the best fitting performance to experimental data (RMSE ≤ 0.050 d-1; R2≥0.804; d2≥0.943). Cultivation conditions conducting photoinhibition were identified in some kinetic models. After testing these models on independent datasets, Bannister and Grima models presented superior predictive performance (RMSE = 0.022-0.023 d-1; R2 = 0.878-0.884; d2: 0.976-0.975). The models provide valuable tools for predicting microalgal growth and optimising operational parameters, reducing the need for time-consuming and costly experiments.

Microalgal cultures for the remediation of wastewaters with different nitrogen to phosphorus ratios: Process modelling using artificial neural networks.

Microalgae have remarkable potential for wastewater bioremediation since they can efficiently uptake nitrogen and phosphorus in a sustainable and environmentally friendly treatment system. However, wastewater composition greatly depends on its source and has a significant seasonal variability. This study aimed to evaluate the impact of different N:P molar ratios on the growth of Chlorella vulgaris and nutrient removal from synthetic wastewater. Furthermore, artificial neural network (ANN) threshold models, optimised by genetic algorithms (GAs), were used to model biomass productivity (BP) and nitrogen/phosphorus removal rates (RRN/RRP). The impact of various inputs culture variables on these parameters was evaluated. Microalgal growth was not nutrient limited since the average biomass productivities and specific growth rates were similar between the experiments. Nutrient removal efficiencies/rates reached 92.0 ± 0.6%/6.15 ± 0.01 mgN L-1 d-1 for nitrogen and 98.2 ± 0.2%/0.92 ± 0.03 mgP L-1 d-1 for phosphorus. Low nitrogen concentration limited phosphorus uptake for low N:P ratios (e.g., 2 and 3, yielding 36 ± 2 mgDW mgP-1 and 39 ± 3 mgDW mgP-1, respectively), while low phosphorus concentration limited nitrogen uptake with high ratios (e.g., 66 and 67, yielding 9.0 ± 0.4 mgDW mgN-1 and 8.8 ± 0.3 mgDW mgN-1, respectively). ANN models showed a high fitting performance, with coefficients of determination of 0.951, 0.800, and 0.793 for BP, RRN, and RRP, respectively. In summary, this study demonstrated that microalgae could successfully grow and adapt to N:P molar ratios between 2 and 67, but the nutrient uptake was impacted by these variations, especially for the lowest and highest N:P molar ratios. Furthermore, GA-ANN models demonstrated to be relevant tools for microalgal growth modelling and control. Their high fitting performance in characterising this biological system can contribute to reducing the experimental effort for culture monitoring (human resources and consumables), thus decreasing the costs of microalgae production.

Microalgal Cultures for the Bioremediation of Urban Wastewaters in the Presence of Siloxanes.

Microalgae are widely used in the bioremediation of wastewaters due to their efficient removal of pollutants such as nitrogen, phosphorus, and contaminants of emerging concern (CECs). Siloxanes are CECs that reach wastewater treatment plants (WWTPs), leading to the production of biogas enriched with these compounds, associated with the breakdown of cogeneration equipment. The biological removal of siloxanes from wastewaters could be a sustainable alternative to the costly existing technologies, but no investigation has been performed using microalgal cultures for this purpose. This study evaluated the ability of Chlorella vulgaris to bioremediate primary (PE) and secondary (SE) urban effluents and remove volatile methylsiloxanes (VMSs). C. vulgaris grew successfully in both effluents, and approximately 86% of nitrogen and 80% of phosphorus were efficiently removed from the PE, while 52% of nitrogen and 87% of phosphorus were removed from the SE, and the presence of VMSs does not seem to have a negative influence on nutrient removal. Three out of the seven of the analysed VMSs were detected in the microalgal biomass at the end of the PE assay. However, dodecamethylcyclohexasiloxane (D6) was the one that accumulated to a greater extent, since 48% of the initial mass of D6 was detected in the biomass samples. D6 is one of the most lipophilic VMSs, which might contribute to the higher adsorption onto the surface of microalgae. Overall, the results indicate C. vulgaris' potential to remove specific VMSs from effluents.

Standardized reactors for the study of medical biofilms: a review of the principles and latest modifications.

Biofilms can cause severe problems to human health due to the high tolerance to antimicrobials; consequently, biofilm science and technology constitutes an important research field. Growing a relevant biofilm in the laboratory provides insights into the basic understanding of the biofilm life cycle including responses to antibiotic therapies. Therefore, the selection of an appropriate biofilm reactor is a critical decision, necessary to obtain reproducible and reliable in vitro results. A reactor should be chosen based upon the study goals and a balance between the pros and cons associated with its use and operational conditions that are as similar as possible to the clinical setting. However, standardization in biofilm studies is rare. This review will focus on the four reactors (Calgary biofilm device, Center for Disease Control biofilm reactor, drip flow biofilm reactor, and rotating disk reactor) approved by a standard setting organization (ASTM International) for biofilm experiments and how researchers have modified these standardized reactors and associated protocols to improve the study and understanding of medical biofilms.

Nitrogen Removal from Landfill Leachate by Microalgae.

Landfill leachates result from the degradation of solid residues in sanitary landfills, thus presenting a high variability in terms of composition. Normally, these effluents are characterized by high ammoniacal-nitrogen (N-NH4⁺) concentrations, high chemical oxygen demands and low phosphorus concentrations. The development of effective treatment strategies becomes difficult, posing a serious problem to the environment. Phycoremediation appears to be a suitable alternative for the treatment of landfill leachates. In this study, the potential of Chlorella vulgaris for biomass production and nutrients (mainly nitrogen and phosphorus) removal from different compositions of a landfill leachate was evaluated. Since microalgae also require phosphorus for their growth, different loads of this nutrient were evaluated, giving the following N:P ratios: 12:1, 23:1 and 35:1. The results have shown that C. vulgaris was able to grow in the different leachate compositions assessed. However, microalgal growth was higher in the cultures presenting the lowest N-NH4⁺ concentration. In terms of nutrients uptake, an effective removal of N-NH4⁺ and phosphorus was observed in all the experiments, especially in those supplied with phosphorus. Nevertheless, N-NO3- removal was considered almost negligible. These promising results constitute important findings in the development of a bioremediation technology for the treatment of landfill leachates.

Biotechnological potential of Synechocystis salina co-cultures with selected microalgae and cyanobacteria: Nutrients removal, biomass and lipid production.

Cultivation of microalgae and cyanobacteria has been the focus of several research studies worldwide, due to the huge biotechnological potential of these photosynthetic microorganisms. However, production of these microorganisms is still not economically viable. One possible alternative to improve the economic feasibility of the process is the use of consortia between microalgae and/or cyanobacteria. In this study, Chlorella vulgaris, Pseudokirchneriella subcapitata and Microcystis aeruginosa were co-cultivated with Synechocystis salina to evaluate how dual-species cultures can influence biomass and lipid production and nutrients removal. Results have shown that the three studied consortia achieved higher biomass productivities than the individual cultures. Additionally, nitrogen and phosphorus consumption rates by the consortia provided final concentrations below the values established by European Union legislation for these nutrients. In the case of lipid productivities, higher values were determined when S. salina was co-cultivated with P. subcapitata and M. aeruginosa.

Metallo-â-lactamase-producing Pseudomonas aeruginosa in two hospitals from southern Brazil

This study determined the prevalence of metallo-â-lactamase (MBL)-producing Pseudomonas aeruginosa in two hospitals located in the Southern part of Brazil and compare the performance of two different phenotypic tests. Thirty-one non-repetitive Pseudomonas aeruginosa isolates from various clinical samples from patients admitted to two hospitals located in Rio Grande do Sul, Brazil (twenty-three from a hospital in Porto Alegre City and eight isolates from a hospital in Vale dos Sinos Region). All strains suggestive of possessing MBLs by phenotypic methods were included in this study. Phenotypic detection of MBLs was carried out simultaneously by using both the MBL Etest® and disk approximation test using 2-mercaptopropionic acid close to a ceftazidime disk. Strains positive were further confirmed using molecular techniques for blaVIM, blaIMP and blaSPM-1. The prevalence of MBLs from samplesof inpatients from the hospital located in Porto Alegre was 30.4 percent and that of inpatients from Vale dos Sinos hospital was only 3.1 percent. Only MBL type SPM-1 was detected in these samples by molecular analysis and all were detected by the Etest® MBL strips. The prevalence of P. aeruginosa that produce MBLs can be markedly different in distinct geographical areas, even among different hospitals in the same area. In our study, the EDTA-based method was the only method able to detect all strains harboring the SPM-1 enzyme.

Metallo-beta-lactamase-producing Pseudomonas aeruginosa in two hospitals from southern Brazil.

This study determined the prevalence of metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa in two hospitals located in the Southern part of Brazil and compare the performance of two different phenotypic tests. Thirty-one non-repetitive Pseudomonas aeruginosa isolates from various clinical samples from patients admitted to two hospitals located in Rio Grande do Sul, Brazil (twenty-three from a hospital in Porto Alegre City and eight isolates from a hospital in Vale dos Sinos Region). All strains suggestive of possessing MBLs by phenotypic methods were included in this study. Phenotypic detection of MBLs was carried out simultaneously by using both the MBL Etest and disk approximation test using 2-mercaptopropionic acid close to a ceftazidime disk. Strains positive were further confirmed using molecular techniques for bla(VIM), bla(IMP) and bla(SPM-1). The prevalence of MBLs from samples of inpatients from the hospital located in Porto Alegre was 30.4% and that of inpatients from Vale dos Sinos hospital was only 3.1%. Only MBL type SPM-1 was detected in these samples by molecular analysis and all were detected by the Etest MBL strips. The prevalence of P. aeruginosa that produce MBLs can be markedly different in distinct geographical areas, even among different hospitals in the same area. In our study, the EDTA-based method was the only method able to detect all strains harboring the SPM-1 enzyme.