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- Biostimulant and biopesticide potential of microalgae growing in piggery wastewaterPublication . Ferreira, Alice; Melkonyan, Lusine; Carapinha, Sofia; Ribeiro, Belina; Figueiredo, Daniel; Avetisova, Gayane; Gouveia, LuisaABSTRACT: Pig farming generates highly polluting wastewaters which entail serious environmental issues when not adequately managed. Microalgae systems can be promising for cost, energy and environment-efficient treatment of piggery wastewater (PWW). Aside from clean water, the produced biomass can be used as biostimulants and biopesticides contributing to a more sustainable agriculture. Three microalgae (Tetradesmus obliquus, Chlorella protothecoides, Chlorella vulgaris) and one cyanobacterium (Synechocystis sp.) were selected after a preliminary screening in diluted wastewater (1:20) to treat PWW. The nutrient removals were 62-79% for COD (chemical oxygen demand), 84-92% for TKN (total Kjeldahl nitrogen), 79-92% for NH4+ and over 96% for PO43−. T. obliquus and C. protothecoides were the most efficient ones. After treating PWW, the produced biomass, at 0.5 g L−1, was assessed as a biostimulant for seed germination, root/shoot growth, and pigment content for tomato, watercress, cucumber, soybean, wheat, and barley seeds. We observed an overall increase on germination index (GI) of microalgae-treated seeds, owing to the development of longer roots, especially in T. obliquus and C. vulgaris treatments. The microalgae treatments were especially effective in cucumber seeds (75-138% GI increase). The biopesticide activity against Fusarium oxysporum was also evaluated at 1, 2.5 and 5 g L−1 of microalgae culture. Except for Synechocystis sp., all the microalgae tested inhibited the fungus growth, with T. obliquus and C. vulgaris achieving inhibitions above 40% for all concentrations.
- New technologies for municipal wastewater treatmentPublication . Ribeiro, Belina; Moreira, Cristina; Pontes, Diogo; Grasmick, Alain; Duarte, José CardosoNew technologies to treat and recycle water from municipal waste water treatment plants are of utmost urgency. This study is taking place on the Mondego River, lower basin and estuary, from Coimbra to Figueira da Foz and contribute for the environmental sustainability of this region. In this work we developed a new treatment system using submerged membrane bioreactors for improved treatment and removal of pollution eliminating particles, bacterial and virus fro the treated effluents. Use of microalgae photoreactors as an alternative tertlary treatment of urban wastewaters was also evaluated. Monitoring and long distance supervision are also possible with the system. The biotreatment process was monitored with an online sensor based on ultra violet spectra technology for continuous analysis of COD, NO3 and TSS. This system eliminates the constant need for samples recollection to further analysis. Supervision is ensured by last generation SCADA software (MOVICON), analyzing in real time all the occurrences and registering all the values in a data base. A new system of at distance supervision and control for urban wastewater treatment plants (WWPT's) was also tested and could allow for better technical performance and economy. Physico-chemical characterisation of local WWTP's and Mondego River were performed, in order to test a kinetic model representative of the impact of WWTP's in the environment.
- Bioprocess to produce biostimulants/biofertilizers based on microalgae grown using piggery wastewater as nutrient sourcePublication . Ferreira, Alice; Corrêa, D. O.; Ribeiro, Belina; Silva, Teresa Lopes da; Santos, Cláudia Marques dos; Acién, F. Gabriel; Gouveia, LuisaABSTRACT: In the present work, two downstream processes - high-pressure homogenization at 100 (HPH-100) and 1200 bar (HPH-1200), and enzymatic hydrolysis (EH) - were tested to produce biostimulant extracts from Tetradesmus obliquus grown in piggery wastewater at two concentrations (12.8 and 88.3 g/L). Extracts before and after centrifugation (C) were evaluated in four bioassays using garden cress (germination), mung bean (auxin-like activity), and cucumber (auxin- and cytokinin-like activity) relative to distilled water. The initial microalgal culture, without any treatment, had the best germination results (162 % at 0.2 g/L) and the only one that showed cytokinin-like activity (141 % at 0.5 g/L). In both auxin-like bioassays, the HPH-1200 + C and EH + C originated high values (186 and 155 % for cucumber, 290 and 285 % for mung bean, respectively). For mung bean, the HPH-1200 achieved the highest auxin-like effect (378 %). Finally, the extracted biomass contained essential nutrients for biofertilization, complementing the biostimulant extracts for sustainable agriculture application.
- Jet-loop reactor with cross-flow ultrafiltration membrane system for treatment of olive mill wastewaterPublication . Ribeiro, Belina; Torrado, Ivone; Di Berardino, Santino; Paixão, Susana M.; Rusan, M. J.; Amer, A. Bani; Zuraiqi, S.; Eusebio, AnaABSTRACT: Olive oil extraction is one of the ancient agricultural industries all over the Mediterranean area and even today it is of fundamental economic importance for many industries found over the whole Mediterranean. However, this industry generates large amounts of olive mill wastewater (OMW) and due to its physicochemical characteristics it causes severe environmental concerns and management problems in the Mediterranean area, which is facing water scarcity. Technologies to reuse this wastewater will have a high impact at the economic and environmental level. The work presented aims to improve the use of jet-loop reactors technology for the aerobic biotreatment of OMW. A jet-loop reactor (100 L) coupled with an ultrafiltration (UF) membrane (MBR) system (JACTO.MBR_100 L) were tested for the influence of hydraulic parameters on OMW degradation and scale-up to 1,000 L. Chemical oxygen demand and total phenols (TP) decreased notably (up to 85% and 80% removal efficiency, respectively) after the biological treatment. The treated OMW (UF permeate) was evaluated as a source for irrigation and its impact on the soil and plant growth and their quality parameters.
- Bioethanol production from agricultural wastesPublication . Duarte, José Cardoso; Sàágua, M. C.; Baeta-Hall, Lina; Correia, Anabela; Ribeiro, Belina; Lourenço, V.; Pereira, J.; Paixão, Susana M.In this study, different strains of Saccharomyces cerevisiae have been screened for the ability of bioethanol production. Yeasts were grown in synthetic liquid medium containing two different substrates: sucrose at different concentrations (10 to 400g/l) and cane molasses (120g/l of sucrose). The screening was made in batch regime and the growth rates, ethanol and biomass productions were determined. The results indicate a flocculent yeast strain – F as the more suitable microorganism to produce ethanol, presenting the highest value of growth rate (0.49h-1) and ethanol yield (0.40g/g) with 120g/l of sucrose concentration. In addition, ethanol production was also studied in a continuous process with the selected yeast strain (F strain), with sucrose and cane molasses (120g/l) at different dilution rates (0.05-0.5 h-1). Data showed that when dilution rate raised to 0.4h-1 the highest sugar conversion, 85% and 90%, were achieved with an ethanol production of 40.5g/l and 50.8g/l for sucrose and molasses, respectively.
- Detoxification of olive mill wastewaters using a packed-bed batch reactorPublication . Paixão, Susana M.; Sàágua, M. C.; Baeta-Hall, Lina; Correia, Anabela; Ribeiro, Belina; Duarte, José CardosoOlive oil production is a traditional agricultural industry in Mediterranean countries and Portugal is one of the ten major producers. This industry generates an effluent, olive mill wastewater (OMW), which does not undergo any treatment and, usually, is stored in evaporation lagoons or spread on the land. Disposal of olive oil mill wastewaters is a serious environmental problem due to its high organic loading, presence of polyphenols and tannins, high content in suspended solids and acidity, which contributes to its ecotoxicity. In this work, a biological treatment system: a packed-bed batch reactor was applied to a Portuguese OMW using its autochthon microbial population as inoculum. Thus, the biodegradation potential of OMW’ microrganisms naturally present in these wastewaters was assessed monitoring several physico-chemical parameters along the process. Ecotoxicity tests (Pseudomonas putida growth inhibition test and Vibrio fisheri growth inhibition test) were carried out to follow the detoxification capacity of the system as well as its potential to be used in the treatment of this type of agroindustrial effluent. In this aerobic treatment, an active microbial community with high degradation ability for the OMW organic load was detected, accounting for 80%, 71% and 61% removal of COD, TSS and phenols, respectively. In addition, a significant decrease in the chronic toxicity of the treated OMW to both bacteria, V. fisheri (62.8%) and P. putida (64.3%), was also observed after 140 days of treatment, highlighting the detoxification potential of the system studied
- From piggery wastewater to wheat using microalgae towards zero wastePublication . Ferreira, Alice; Figueiredo, Daniel; Ferreira, Francisca; Marujo, Ana; Bastos, Carolina R. V.; Martin-Atanes, Guillermo; Ribeiro, Belina; Štěrbová, Karolína; Santos, Cláudia Marques dos; Acién, F. Gabriel; Gouveia, LuisaABSTRACT: Microalgae production is still expensive, driving the need to lower costs while strengthening the industry's environmental sustainability. Microalgae are recognized tools for efficient wastewater treatment, offering the recycling of nutrients and water for agriculture, and producing biomass rich in growth-promoting compounds to improve plant productivity and resistance to adverse conditions. The use of wastewater can reduce cultivation costs as it is a source of nutrients and water. Alternative low-cost methods can significantly decrease harvesting costs, which represents one of the most expensive steps of the whole process.The goal of this work was to evaluate the potential of wastewater-grown microalga biomass for agriculture purposes. To reduce production costs, the microalga Tetradesmus obliquus was produced in pre-treated photo-Fenton (PF) piggery wastewater in combination with the use of different harvesting techniques - electro-coagulation, flocculation, and centrifugation, and different combinations. From the wastewater treatment pro-cess, two fractions (biomass and supernatant) were evaluated for germination and growth of wheat (Triticum aestivum L.) plants and compared to non-harvested microalga culture (MC), distilled water, and Hoagland (synthetic) solution. The concentrated resulting from PF was also tested as a biofertilizer.The results confirm that both biomass and supernatants are useful for agricultural applications. The obtained biomass elicited a 20-105 % increase in germination index compared to the control, while supernatants were inhibiting. The opposite trend was observed at later stages of wheat growth, where the nutrient-enriched su-pernatants and the PF concentrate (PF-CC) increased the number of tillers (3-5) and leaves (30-42) after 83 days. Wheat plants treated with MC and PF-CC produced similar number of ears (3.4 & PLUSMN; 0.5 and 6.0 & PLUSMN; 4.1 ears per plant, respectively) than the synthetic control (5.7 & PLUSMN; 1.4) after 182 days. All fractions obtained from the process can be used in a zero-waste process.
- Oleico+ sustainability in the olive mill waste managementPublication . Ribeiro, Belina; Duarte, José Cardoso; Santori, Francesca; Auguto, GrabrielaOlive oil production generates olive mill wastes estimated at 2.5 million tonnes. More than 80% of olive mill wastes consist in water. Olive mill wastewater (OMW) has environmental impacts due to its high organic load and contents in phenols, lipids and organic acids. The project Oleico +, supported by the European Program LIFE, brought together 4 Institutions from 4 European Member States to seek and select a set of environmental friendly technologies for the remediation or valorization of olive mill wastes, and to raise the awareness of olive oil stakeholders for an environmental sustainable olive mill waste management. The OLEICO + project selected eight technologies to manage olive mill wastes that may be applied to different olive mill systems and amounts of waste generated. This selection was performed with a point to grid classification of technologies sustainability and status. To access eco-sustainability several parameters were accounted, including carbon dioxide emissions, landscape impacts and bead smells. Eleven technologies were selected out of 28 inventoried. Specifically five of these technologies deal with OMW and its detoxification, and four of them produce reusable water for irrigation. Other three technologies are focused in the energetic and or agronomic valorization of olive mill wastes. Some of these technologies present positive net income values, a many of them do not require specialized workforce, but the small dimension of olive mills make the management of olive mill wastes a challenge for the industry
- Combining biotechnology with circular bioeconomy: from poultry, swine, cattle, brewery, dairy and urban wastewaters to biohydrogenPublication . Ferreira, Alice; Marques, Paula; Ribeiro, Belina; Assemany, Paula; Vieira De Mendonça, Henrique; Barata, Ana; Oliveira, Ana Cristina; Reis, Alberto; Pinheiro, H. M.; Gouveia, LuisaABSTRACT: The ability of microalgae to grow in nutrient-rich environments and to accumulate nutrients from wastewaters (WW) makes them attractive for the sustainable and low-cost treatment of WW. The valuable biomass produced can be further used for the generation of bioenergy, animal feed, fertilizers, and biopolymers, among others. In this study, Scenedesmus obliquus was able to remove nutrients from different wastewaters (poultry, swine and cattle breeding, brewery and dairy industries, and urban) with removal ranges of 95-100% for nitrogen, 63-99% for phosphorus and 48-70% for chemical oxygen demand. The biomass productivity using wastewaters was higher (except for poultry) than in synthetic medium (Bristol), the highest value being obtained in brewery wastewater (1025 mg/(L.day) of freeze-dried biomass). The produced biomass contained 31-53% of proteins, 12-36% of sugars and 8-23% of lipids, regardless of the type of wastewater. The potential of the produced Scenedesmus obliquus biomass for the generation of BioH(2) through batch dark fermentation processes with Enterobacter aerogenes was evaluated. The obtained yields ranged, in mL H-2/g Volatile Solids (VS), from 50.1 for biomass from anaerobically digested cattle WW to 390 for swine WW, whereas the yield with biomass cultivated in Bristol medium was 57.6 mL H-2/gvs.
- Strategies for the purification of hydroxytyrosol-rich extracts obtained from exhausted olive pomacePublication . Gómez Cruz, Irene; Contreras, Maria del Mar; Romero, Inmaculada; Ribeiro, Belina; Roseiro, Luisa B.; Duarte, Luís C.; Carvalheiro, Florbela; Castro, EulogioABSTRACT: Exhausted olive pomace (EOP) is a residual biomass from which hydroxytyrosol can be recovered. This compound has applications in the food/pharma sectors, but its extraction yields complex extracts that require further purification for some applications. This work explores purification strategies based on membrane technology, liquid–liquid extraction (LLE), and solid-phase extraction with adsorbents and resins. The hydroxytyrosol content, phenolic profile, antioxidant activity, and inhibition of α-glucosidase and α-amylase were monitored. Hydroxytyrosol stood out in all purified extracts. The best hydroxytyrosol recovery (88.8%) was achieved using LLE with ethyl acetate as the extractant, while the purest extracts in phenolic compounds, including hydroxytyrosol, were obtained using the latter solvent and C18 (529 mg/g), DSC-8 (873 mg/g), and Purosorb PAD910 (523 mg/g). Conversely, mannitol and glucose, at high concentrations in the extract, were selectively retained in the aqueous phases. The developed strategies are discussed regarding their suitability to provide hydroxytyrosol-concentrated extracts, up to 291 mg/g, with antioxidant and antidiabetic functionalities.
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