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Browsing UB - Artigos em revistas internacionais by Field of Science and Technology (FOS) "Engenharia e Tecnologia::Biotecnologia Ambiental"
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- Assessment of piggery wastewater treatment in vertical flow constructed wetlands: role of plants and aerationPublication . de Oliveira Corrêa, Diego; Ferreira, Alice; Ribeiro, Belina; Gogoi, Jayanta; Karan, N.; Nalwad, A.; Ganguly, A.; Mutnuri, S.; Gouveia, LuisaABSTRACT: Piggery wastewater (PWW), rich in pollutants, poses significant environmental risks if not properly treated. Natural treatment processes, such as constructed wetlands (combined action of plants, substrates, and microbes) and microalgae cultivation, offer sustainable and low-cost alternatives for managing these effluents while enabling resource recovery. This study represents an initial step toward optimizing key operational conditions, such as aeration (passive and active), vegetation presence, and the use of single or sequential Vertical Flow Constructed Wetlands (VFCWs), for the treatment of piggery wastewater, using different experimental setups, at a laboratory scale. Indoor experiments were conducted over an 8-week period to optimize operational conditions for the treatment of PWW. The VFCWs, arranged in two stages and operated in series through gravity flow, were fed daily and monitored weekly. The best removal rates of total Kjeldahl nitrogen (42.9 %), ammoniacal nitrogen (50.3 %), and chemical oxygen demand (20.5 %), were observed in the second stage of VFCW without aeration and with plant. Nitrate and phosphorus levels increased during the experiment, likely due to microbial activity within the substrate and plant root zones. The final goal is to treat the piggery wastewater from a rural farm in India, produce electricity (by a Microbial Fuel Cell), to generate an effluent suitable for microalgae cultivation, with the produced biomass intended for use either as a biostimulant to enhance cereal crops included in pig diets or as a direct nutritional supplement in pig feed.
- Benchmarking commercially available value-added fractions with potential for production via microalgae-based biorefineries: is it worth it?Publication . Ferreira, Flávio; Reis, Alberto; Ortigueira, Joana; Lopes, TiagoABSTRACT: The urgent need to mitigate climate change requires finding sustainable and efficient alternatives to fossil fuel-based materials. Biosequestration by microalgae has been suggested as a potential method for climate change mitigation due to its environmentally friendly nature and ability to produce high-value compounds. However, the large-scale application of microalgal biorefineries faces significant challenges, particularly in the harvest and processing stages, which are often costly and energy-intensive. This study aims to benchmark value-added fractions that can be produced via microalgae-based biorefineries against their commercially available counterparts. A systematic review was conducted using the Web of Science™ database to identify current commercial sources of proteins, lipids, polyunsaturated fatty acids and pigments, this study identified key sectors and applications for each fraction, as well as potential market competitors. The results highlight substantial cost differences across production systems, with traditional agricultural sources demonstrating lower CAPEX but greater environmental challenges. Meanwhile, microalgal systems, although associated with higher CAPEX, offer advantages such as reduced land and water dependency, potentially leading to long-term economic resilience and environmental sustainability. By pinpointing research trends, key sectors and optimization opportunities, this work offers valuable insights into the profitability and competitiveness of microalgal systems, providing a benchmark for future optimization efforts. The novelty of this research lies in its comprehensive comparison of microalgae-based and traditional production systems, establishing a clear benchmark for microalgal production and suggesting focus areas for enhancement.
- Bio-oil from hydrothermal liquefaction of microalgae cultivated in wastewater: An economic and life cycle approachPublication . Silva, Thiago; Junior, Maurino Magno de Jesus; Magalhães, Iara; Ananias, Marina Stefany; Saleme Aona de Paula Pereira, Alexia; Rodrigues, Fábio de Ávila; Delgado dos Reis, Alberto José; Calijuri, Maria LuciaABSTRACT: Although microalgae are a promising sustainable biofuel feedstock, their energy-intensive production and most environmental assessments rarely achieve the desired trade-off between productivity and sustainability. In this context, this study aims to evaluate the economic and environmental feasibility of producing bio-oil via hydrothermal liquefaction (HTL) of wastewater-grown microalgae at an industrial scale. Four scenarios varied production scale and steam source: sugarcane bagasse (SCB) in SC1 and SC3, liquefied petroleum gas (LPG) in SC2 and SC4. Each scenario processed microalgae at 300 degrees C for 30 min. Smaller-scale feedstock (1332.9 kg/h) in SC1 and SC2 produced 34.6 kg/h of bio-oil, while the larger feedstock (85,554.4 kg/h) in SC3 and SC4 yielded 2222.2 kg/h. Microalgae biomass cultivation costs dominated overall expenses (56-75 %). Economic analyses indicated minimum selling prices of 3.82-8.52 USD/kg, exceeding the average literature figure of 1.57 USD/kg. Life Cycle Assessment (LCA) showed SCB reduced fossil resource depletion by 14.97 % compared to LPG but increased emissions of nitrogen oxides, particulates, and toxic compounds, which are manageable via selective catalytic reduction and flue gas desulphurization. Cyclohexane as a solvent elevated human carcinogenic toxicity, greener alternatives could reduce toxicity but may cost more, requiring further cost analysis. Advancing this biorefinery route requires optimization of cultivation and processing costs, adoption of environmentally benign solvents, and implementation of emission control strategies to enable economically feasible and environmentally sustainable bio-oil production.
- Consortium of microalgae/nitrogen-fixing bacteria as a next-generation biofertilizer, biostimulant and biopesticidePublication . Gouveia, Luisa; Ferreira, Alice; Bastos, Carolina R. V.; Avetisova, Gayane; Karapetyan, Zh.; Toplaghaltsyan, A.; Melkonyan, LusineABSTRACT: This study aims to provide insights into a new consortium of a microalga, twelve nitrogen-fixing (N-fixing) bacteria and a cyanobacterium. The microalga Tetradesmus obliquus (T), in conjunction with various N-fixing bacteria and the cyanobacterium Synechocystis sp. PCC 6803 (S), the N-fixing bacterium Sphingobacterium sp. L13G8 (5), cultivated in complete Bristol medium and in Bristol-NaNO3 free conditions, were examined. The study encompassed the analysis of their consortia, including evaluation of their growth, and potential as a biostimulant, biofertilizer and biopesticide, and assessed for sedimentation performance for targeted applications. The T and N-fixing bacteria consortia had higher growth in Bristol NaNO3-free media. The triple culture TS5 had the highest growth parameter (2.4 OD540) in the same medium, followed by T5. The consortia were employed to ascertain the efficacy of their biostimulants and biofertilizers on watercress (Lepidium sativum) and to determine the potency of their biopesticides against the fungal pathogens Fusarium oxysporum and Rhizoctonia solani (in certain consortia). Consortium T5 demonstrated the most significant impact on the seeds germination index (212.7%) and root length (6.0 cm) of L. sativum. The same consortium had a significant impact on the shoot length (4.4 cm) of L. sativum. Among all consortia that were examined, T5 exhibited significant inhibitory effects on the growth of F. oxysporum (60.6%) and R. solani (69.2%). In the same consortium, the rate of microalgal biomass sedimentation was enhanced by the N-fixing bacterium (0.4 cm h-1). Consortium T5 was the most effective in relation to growth and biomass sedimentation efficiency, in addition to its use as a biostimulant, biofertilizer and biopesticide. The created combination of microalga and N-fixing bacterium represents significant progress in the field of microalga cultivation, with notable benefits including improved biomass sedimentation and enhanced agricultural practices, as well as environmental friendliness and safety.
- Editorial: The biorefineries and application of green technologies for recovering bioactive compounds from microalgaePublication . Vladic, Jelena; Gouveia, LuisaABSTRACT: Microalgae are attracting growing scientific and industrial interest as a renewable and versatile source of high-value bioactive compounds, including pigments, fatty acids, proteins, and antioxidants. Their rapid growth, ability to adapt to extreme conditions, and rich biochemical composition make them a promising resource for sustainable development across a range of applications. From cosmetics to food supplements, their potential spans multiple industries. Still, the considerable gap between encouraging laboratory research and commercially viable production remains. One of the major challenges lies in developing methods for extracting and preserving these compounds in ways that are both efficient and environmentally responsible.
- Energy potential of elephant grass broth as biomass for biogas productionPublication . da Silva, Guilherme Henrique; Renato, Natalia dos Santos; Coelho, Felipe Ferreira; Donato, Thiago Paiva; Otenio, Marcelo; Machado, Juarez; Delgado dos Reis, Alberto JoséABSTRACT: The growing demand for clean energy has highlighted plant biomass as a valuable alternative, supporting sustainable development goals. Elephant grass (EG) is a promising feedstock due to its adaptability to diverse soils and climates, high dry matter production, and substantial energy yield. This study aimed to evaluate and characterize six selected EG genotypes (BRS Capia & ccedil;u, T_23.1, T_23.2, T_41.2, T_47.1, and T_51.5) based on their broth productivity and energy yield. Analysis of the broth's yield and physicochemical properties revealed that the by-product extracted from the biomass had a high residual energy value. Additionally, extracting the broth reduces the grass's biomass moisture content, enhancing its calorific value and improving the bagasse quality for combustion in boilers, thus optimizing energy production. This study demonstrates that the promising EG genotypes T_47.1, T_41.2, and T_23.1 presented relevant energy values ranging from 4248.12 to 4304.06 kcal kg- 1 of bagasse and thus are suitable for energy production through direct combustion. The extracted broth is a valuable residual energy source that can be utilized industrially after anaerobic digestion. Future research should focus on the environmental and economic effectiveness of EG broth as an energy source from waste and its potential for biogas production.
- Extraction and assessment of the colouring capacity of Arthrospira platensis-derived pigmentsPublication . Villaro-Cos, Silvia; Gouveia, Luisa; Vladic, Jelena; Sanchez-Zurano, Ana; Martínez-García, Irene; Lafarga, TomásABSTRACT: This study presents a zero-waste biorefinery approach for the sequential extraction of phycocyanin and chlorophyll from Arthrospira platensis, followed by the valorisation of the remaining biomass as a plant biostimulant. Natural deep eutectic solvents were screened for phycocyanin recovery, with the mixture proline:glycerol:sorbitol:water (1:1:1:13 molar ratio) showing the highest potential (1.15 g⋅100 g-1; p < 0.05). An initial ultrasound-assisted cell wall disruption step significantly enhanced phycocyanin yield by 400–450 % relative to the untreated control (p < 0.05). A response surface methodology optimised extraction achieved a recovery yield of 8.26 g⋅100 g-1 at 39.7 °C and 127.9 min. The phycocyanin-rich extract was used to mimic the blue colour of commercial blue gin, with a minimal colour difference (ΔE) of 4.53. Subsequent chlorophyll extraction from the phycocyanin leftovers yielded an extract that successfully coloured a commercial green alcohol-free apple liquor (ΔE = 3.93) and green gin (ΔE = 1.65). Finally, the residual biomass demonstrated a significant biostimulant capacity, increasing the germination index of various seeds by 80–150 % compared to water (p < 0.05). This work highlights the potential of A. platensis as a sustainable source for natural colourants and agricultural inputs.
- Integrating social aspects in microalgal biorefineries: a Product Social Impact Life Cycle Assessment (PSILCA) approachPublication . Ortigueira, Joana; Lopes, Tiago; Reis, Alberto; Gírio, FranciscoABSTRACT: The ongoing climate change phenomenon requires the reduction of atmospheric CO2 concentrations. Microalgal biorefineries, which convert atmospheric CO2 into chemical energy, offer a viable alternative to fossil fuel-based industrial systems. This study assesses the social impacts of microalgal biorefineries using the Product Social Impact Life Cycle Assessment database approach, focusing on an industrial facility located in P & oacute;voa de Santa Iria, Vila Franca de Xira, Portugal. The foreground system involves the production of microalgae in cascade raceway systems, followed by their refinement into protein, lipid and carbohydrate fractions. Dedicated surveys were distributed to the local community to collect social data, which was then analyzed using the Product Social Impact Life Cycle Assessment (PSILCA) database and a newly designed evaluation schema. Preliminary data from approximately 300 valid responses indicated that the local community faces a medium risk of being unfamiliar with the concept of microalgae or its benefits but acknowledged the high probability of local economic benefits and job creation upon implementation. The study highlights a general lack of familiarity with microalgae among the local community, which could affect the acceptance of the biorefinery. Although the PSILCA approach identifies social hotspots effectively, reliance on generic data may not accurately represent the local context. The study underscores the need for enhanced information dissemination to improve community acceptance and support for microalgal biorefineries. Preliminary data collection and analysis highlight the potential for social benefits, but further research is required to address the identified limitations.
- Microalgae-associated Stenotrophomonas maltophilia enhances lutein production and biostimulant activity in Monoraphidium spPublication . Manoel, João; Štěrbová, Karolína; Saini, Mohit Kumar; Barcenas-Perez, Daniela; Cheel, José; Grivalsky, Tomás; Lakatos, Gergely Erno; Lukes, Martin; Urajová, Petra; Ferreira, Alice; Figueiredo, Daniel; Gouveia, Luisa; Masojidek, Jiri; Saurav, KumarABSTRACT: Photosynthetic organisms like microalgae can collect solar energy and transform it into biochemical compounds as other forms of energy that can be utilized in metabolic processes. In nature, microalgae coexist with bacterial communities and may maintain a symbiotic relationship. In the current study, a heterotrophic bacterium, Stenotrophomonas maltophilia was isolated from the phycosphere of a cold-adapted green microalga Monoraphidium sp. (further abbreviated as Monoraphidium). By using advanced liquid chromatography-high-resolution tandem mass spectrometry (LC-HRMS/MS), we were able to detect homoserine lactones (HSLs): 3OHC12-HSL, 3OHC10-HSL, 3OHC14-HSL, C10-HSL, C8-HSL, and OC14-HSL, produced by S. maltophilia. Further, the role of this bacterium in establishing intricate relationships and its implication on biotechnological potential was evaluated. Significant improvements were found in the lutein production of the Monoraphidium culture with bacterial supplements, achieving about 19.3 +/- 0.88 mg g-1 DW of this carotenoid compared to 13.7 +/- 1.87 mg g-1 DW in the control, which represents an increase of about 40 %. Furthermore, the biostimulant potential of Monoraphidium was evaluated using the germination tests with tomato and barley seeds. A higher germination index was observed with improvements of 55 % in tomato and 110 % in barley, respectively, as compared to the control culture, which was related to the microalgae's growth stage. The role of the bacterium was evaluated in how the intricate relationships with the microalgal culture can affect its biotechnological potential (e.g., biostimulant activity and lutein production). The current work expands our knowledge towards designing an efficient polyculture based on complementary traits and metabolic potential to maximize the yield and bioactivity in algal biotechnology.
- Modulating microalgal metabolism and its integration into dark fermentation: Challenges and opportunities with wastewater-grown biomassPublication . Ferreira, Jessica; Silva, Thiago; Saleme Aona de Paula Pereira, Alexia; Reis, Alberto; Zaiat, Marcelo; ; Calijuri, Maria LuciaABSTRACT: Microalgae represent a promising feedstock for the sustainable production of bioproducts and bioenergy, due to their versatile biochemical composition and environmental adaptability. Given the wide range of bioproducts that can be derived from their biomass, its biochemical composition suggests more favorable conversion routes and can be enhanced through cultivation conditions focused on the synthesis of one (or more) metabolites of interest to the biotechnology market. Accordingly, this review focuses on approaches for modulating microalgal metabolism, such as nutrient depletion and reactor configuration characteristics, among others, as well as on key outcomes obtained through two-stage cultivation, which combine phases of high biomass and metabolite productivity. From a resource recovery perspective, emphasis was placed on approaches that are more readily applicable to wastewater treatment plants. Furthermore, as energy-oriented routes are more suitable for valorizing of biomass grown in wastewater and considering that biohydrogen has been shown to be an emerging product of scientific relevance, this review also analyzes the limitations and strategies for integrating its production via dark fermentation. Pretreatment techniques and co-fermentation approaches were discussed as strategies to overcome the challenges associated with the anaerobic fermentation/digestion of microalgae due to their characteristics and biochemical composition. Finally, biorefinery configurations that integrate these processes were discussed from a scale-up perspective.