Browsing by Author "Batista, Ana Paula"
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- Biohydrogen fermantative production : energetic valorization of microalgae biomassPublication . Batista, Ana Paula; Ortigueira, Joana; Gouveia, Luisa; Marques, Paula; Alves, Luís; Moura, PatríciaRenewable, sustainable and carbon-neutral energy production is needed to deal with the challenges of growing energy demand and climate change. Hydrogen (H2) is most promising in the succession of fuel evolution, with several technical, socio-economic and environmental benefits to its credit [1]. It is an excellent energy carrier as it has the highest energy content per unit weight/mass of any known fuel (142 kJ/g) and upon oxidation produces only water [1]. H2 is being explored for use in combustion engines and fuel-cell electric vehicles, and it is expected that H2 demand increases significantly in the near and long term [2]. Biological hydrogen production processes are found to be more environmentally friendly and less energy intensive as compared to thermochemical and electrochemical processes [1]. In dark fermentation, carbohydrate-rich substrates can be used to produce bioH2 in a process mediated by hydrogenase enzymes of anaerobic microorganisms. Moreover, residues and byproducts from agricultural and food industries or wastewaters can be used, providing inexpensive energy generation with simultaneous waste treatment [3]. Recently, there has been an increasing interest on using microalgal biomass for biofuels production. Besides oil extraction for biodiesel purposes [4] or sugar extraction for bioethanol production [5-6], microalgal biomass can also be fermented into bioH2. In this work, Scenedesmus obliquus biomass was used as feedstock for biohydrogen production by Enterobacter aerogenes and Clostridium butyricum. The concentration of microalgal biomass used as fermentation substrate was optimized for each microorganism: 2.5 g/L for E. aerogenes and 50 g/L for C. butyricum. The values of hydrogen production by using “wet” (75% moisture) and dried (oven, 80°C) microalgal biomass were compared, as the suppression of an intermediate biomass drying step is economically advantageous. The highest H2 yield (113.1 mL/g algaAFDW) was attained by C. butyricum with dried microalgal biomass. Hydrogen production by E. aerogenes was clearly improved by using S. obliquus wet biomass, generating an H2 yield of 72.3 mL/g algaAFDW
- Biological hydrogen production by Anabaena sp. – Yield, energy and CO2 analysis including fermentative biomass recoveryPublication . Ferreira, Ana F.; Marques, Ana C.; Batista, Ana Paula; Marques, Paula; Gouveia, Luisa; Silva, Carla M.This paper presents laboratory results of biological production of hydrogen by photoautrotophic cyanobacterium Anabaena sp. Additional hydrogen production from residual Cyanobacteria fermentation was achieved by Enterobacter aerogenes bacteria. The authors evaluated the yield of H2 production, the energy consumption and CO2 emissions and the technological bottlenecks and possible improvements of the whole energy and CO2 emission chain. The authors did not attempt to extrapolate the results to an industrial scale, but to highlight the processes that need further optimization. The experiments showed that the production of hydrogen from cyanobacteria Anabaena sp. is technically viable. The hydrogen yield for this case was 0.0114 kgH2/kgbiomass which had a rough energy consumption of 1538 MJ/MJH2 and produced 114640 gCO2/MJH2. The use of phototrophic residual cyanobacteria as a substrate in a dark-fermentation process increased the hydrogen yield by 8.1% but consumed 12.0% more of energy and produced 12.1% more of CO2 showing that although the process increased the overall efficiency of hydrogen production it was not a viable energy and CO2 emission solution. To make cyanobacteria-based biofuel production energy and environmentally relevant, efforts should be made to improve the hydrogen yield to values which are more competitive with glucose yields (0.1 kgH2/kgbiomass). This could be achieved through the use of electricity with at least 80% of renewables and eliminating the unessential processes (e.g.pre-concentration centrifugation).
- A biorefinery from Nannochloropsis sp. microalga – Energy and CO2 emission and economic analysesPublication . Ferreira, Ana F.; Ribeiro, Lauro A.; Batista, Ana Paula; Marques, Paula; Nobre, B. P.; Palavra, António F.; Silva, Patricia P. da; Gouveia, Luisa; Silva, Carla M.Are microalgae a potential energy source for biofuel production? This paper presents the laboratory results from a Nannochloropsis sp. microalga biorefinery for the production of oil, high-value pigments, and biohydrogen (bioH2). The energy consumption and CO2 emissions involved in the whole process (microalgae cultivation, harvest, dewater, mill, extraction and leftover biomass fermentation) were evaluated. An economic evaluation was also performed. Oil was obtained by soxhlet (SE) and supercritical fluid extraction (SFE). The bioH2 was produced by fermentation of the leftover biomass. The oil production pathway by SE shows the lowest value of energy consumption, 177-245 MJ/MJprod, and CO2 emissions, 13–15 kgCO2/MJprod. Despite consuming and emitting c.a. 20% more than the SE pathway, the oil obtained by SFE, proved to be more economically viable, with a cost of 365€/kgoil produced and simultaneously extracting high-value pigments. The bioH2 as co-product may be advantageous in terms of product yield or profit.
- A biorefinery from Nannochloropsis sp. microalga – Extraction of oils and pigments. Production of biohydrogen from the leftover biomassPublication . Nobre, B. P.; Villalobos, Fidel; Barragan, Blanca E; Oliveira, Ana Cristina; Batista, Ana Paula; Marques, Paula; Mendes, Rui L.; Sovová, H.; Palavra, António F.; Gouveia, LuisaThe microalga Nannochloropsis sp. was used in this study, in a biorefinery context, as biomass feedstock for the production of fatty acids for biodiesel, biohydrogen and high added-value compounds. The microalgal biomass, which has a high lipid and pigment content (mainly carotenoids), was submitted to supercritical CO2 extraction. The temperature, pressure and solvent flow-rate were evaluated to check their effect on the extraction yield. The best operational conditions to extract 33 glipids/100 gdry biomass were found to be at 40 °C, 300 bar and a CO2 flow-rate of 0.62 g/min. The effect of adding a co-solvent (ethanol) was also studied. When supercritical CO2 doped with 20% (w/w) ethanol was used, it was possible to extract 45 glipids/100 gdry biomass of lipids and recover 70% of the pigments. Furthermore, the remaining biomass after extraction was effectively used as feedstock to produce biohydrogen through dark fermentation by Enterobacter aerogenes resulting in a hydrogen production yield of 60.6 mL/gdry biomass.
- Bioremediation of piggery effluents using Scenedesmus Obliquus microalga [Resumo]Publication . Batista, Ana Paula; Mirón, Vicente; Ribeiro, Belina; Silva, Teresa Lopes da; Barragán, Blanca E.; Gouveia, Luisa; Marques, Isabel PaulaEffluents from intensive pig farms present high nutrient concentration, mainly ammonium, contributing to water eutrophication and pollution. Microalgae ability to deplete inorganic nutrients makes them an efficient effluent bioremediation tool. Scenedesmus obliquus was grown in piggery effluent (without any pretreatment) diluted with tap water at 5%v/v (187±25mg/L N-NH4+) and compared with growth in synthetic Bristol media. A 21-days trial was performed in 1L bubble-column reactors illuminated by fluorescent and LED lamps(3klux). Microalgae growth was monitored through OD540nm, dry weight and Chlorophyll content and also by flow cytometry in terms of autofluorescence read in FL3 channel (>670 nm), cell size (FSC), internal complexity (SSC) and cell membrane integrity (PI). S. obliquus cells have grown slower in pig effluent (mmax=0.13-19d-1) than in Bristol media (mmax=0.46-0.50d-1) although after 15 days the biomass productivity observed for the pig waste cultivation, operated under LED (0.127gL-1d-1) was similar to those attained for the Bristol media after 8 and 12 days (0.130 and 0.129 gL-1d-1 using Fluorescent and LED lights, respectively). The Chlorophyll content was correlated to FL3 autofluorescence, with R2>0.97 for Bristol and R2>0.92 for pig waste cultures. Regarding cell size and complexity, Bristol cultures did not show significant differences along time, while cells grown on pig waste increased, attaining FSC and SSC values similar to those observed for Bristol cultures. However, pig waste led to higher percentage of cells with permeabilised membrane (up to 18%) than Bristol cultures (7%). For pig waste experiments, ammonium removal rates were 95% with final values within legal limits. S. obliquus cultivations proved to be an efficient system for direct piggery effluent bioremediation, attaining biomass productivities similar to those obtained in synthetic media. Using LED lighting enables to reduce the energy consumption while maintaining microalgae growth and bioremediation performance. Scale-up to an outdoor 150L photobioreactor is underway.
- Carbon dioxide biofixation and lipid accumulation by green microalgae species at different CO2 concentrations [Resumo]Publication . Leonardo, Joana; Batista, Ana Paula; Manoel, João; Reis, Alberto; Marques, Paula; Gouveia, Luisa
- Co-digestion of Rhodosporidium toruloides biorefinery wastes for biogas productionPublication . Batista, Ana Paula; Coelho, Aldo; Silva, Teresa Lopes da; Marques, Isabel PaulaABSTRACT: Rhodosporiodum toruloides NCYC 921 yeast biorefinery is able to simultaneously provide a gaseous energy carrier, lipids and high-value carotenoids, either using glucose or carob pulp syrup as carbon source in the cultivation step for biomass production. The resulting leftover materials from the yeast biorefinery (YR- de-oiled yeast biomass residue, GS- glucose supernatant, CS- carob supernatant and CR- carob residue) were valued through anaerobic digestion in different mixtures, according to the generated effluents volume. Biogas productions of 55, 31 and 29 mL and methane yield of 236, 179 and 144 mL CH4/g substrate volatile solids (VS) were recorded for the studied mixtures MIX I (YR + GS), MIX II (YR + CS) and MIX III (YR + CS + CR) respectively. The comparison between the biogas production and volatile solids removal obtained for the individual substrates and for the admixtures substrates digestions revealed that co-digestion favoured the conversion of the biorefinery wastes into biogas/methane. Flow cytometry analysis of cells stained with propidium iodide revealed that the proportion of cells with injured membrane was lower in the substrate mixtures digestions than in the individual waste digestions, indicating that co-digestion mitigates the negative effect of potential toxic compounds present in the wastes or produced during the process digestion on the microbial consortium.
- Combining urban wastewater treatment with biohydrogen production: An integrated microalgae-based approachPublication . Batista, Ana Paula; Ambrosano, Lucas; Graça, Sofia; Sousa, Catarina; Marques, Paula; Ribeiro, Belina; Botrel, Elberis P.; Neto, Pedro Castro; Gouveia, LuisaThe aim of the present work was the simultaneous treatment of urban wastewater using microalgae and the energetic valorization of the obtained biomass. Chlorella vulgaris (Cv), Scenedesmus obliquus (Sc) and a naturally occurring algal Consortium C (ConsC) were grown in an urban wastewater. The nutrient removals were quite high and the treated water fits the legislation (PT Dec-Lei 236/98) in what concerns the parameters analysed (N, P, COD). After nutrient depletion the microalgae remained two more weeks in the photobioreactor (PBR) under nutritional stress conditions, to induce sugar accumulation (22–43%). The stressed biomass was converted into biohydrogen (bioH2), a clean energy carrier, through dark fermentation by a strain of the bacteria Enterobacter aerogenes. The fermentation kinetics were monitored and fitted to a modified Gompertz model. The highest bioH2 production yield was obtained for S. obliquus (56.8 mL H2/gVS) which was very similar when using the same algae grown in synthetic media.
- Comparison of microalgal biomass profiles as novel functional ingredient for food productsPublication . Batista, Ana Paula; Gouveia, Luisa; Bandarra, Narcisa M.; Franco, J. M.; Raymundo, AnabelaMicroalgae are one of the most promising sources for new food and functional food products, and can be used to enhance the nutritional value of foods, due to their well-balanced chemical composition. Knowing their physicochemical characteristics is fundamental for the selection of the most suitable microalgae to specific food technology applications and consequently successful novel foods development. The aim of this study is to screen the chemical composition (e.g., proteins, pigments, fatty acids) and thermogravimetry properties of five microalgae species with potential application in the food industry: Chlorella vulgaris (green and carotenogenic), Haematococcus pluvialis (carotenogenic), Spirulina maxima, Diacronema vlkianum and Isochrysis galbana. C. green and S. maxima presented high protein (38% and 44%, respectively), low fat content (5% and 4%, respectively). The carotenogenic C. vulgaris and H. pluvialis showed a higher carotenoid content, higher fat, low protein and better resistance to thermal treatment. D. vlkianum and I. galbana presented high protein (38–40%) and fat (18–24%) contents with PUFA's?3, mainly EPA and DHA. Finally, the results from microalgae chemical and thermal analysis were grouped and correlated through Principal Components Analysis (PCA) in order to determine which variables better define and differentiate them.
- Effect of dietary n-3 PUFA from microalgae on blood, liver, brain, kidney and heart lipidsPublication . Bandarra, Narcisa M.; Duarte, D.; Pinto, R.; Sampayo, C.; Ramos, M.; Batista, I.; Nunes, M. L.; Batista, Ana Paula; Raymundo, Anabela; Gouveia, Luisa; Lima, B. Silva
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