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- A biorefinery approach for the simultaneous production of biofuels and bioplastics [Poster]Publication . Ortigueira, Joana; Leite, T.; Pereira, J.; Serafim, L.S.; Silva, Carla; Moura, Patrícia; Lemos, Paulo Costa
- Energy requirement and CO2 emissions of bioH2 production from microalgal biomassPublication . Ferreira, Ana F.; Ortigueira, Joana; Alves, Luís; Gouveia, Luisa; Moura, Patrícia; Silva, Carla M.This paper presents the life cycle inventory (LCI) of hydrogen production by Clostridium butyricum fermentation of Scenedesmus obliquus hydrolysate. The main purpose of this work was to evaluate the potential of H2 production from microalgal biomass and the respective energy consumption and CO2 emissions in the bioconversion process considering the microalga production, acid hydrolysis of S. obliquus biomass, preparation of the inoculum and culture media, and fermentation. The scale-up to industrial production was not envisaged. The hydrogen yield obtained in this work was 2.9 ± 0.3 mol H2/mol sugars in S. obliquus hydrolysate. Results show that this process of biological production of hydrogen can achieve 7270 MJ/MJH2 of energy consumption and 670Kg CO2/MJH2. The microalgal culture is the stage responsible for 98% of these total final values due to the use of artificial lighting. All stages and processes with the highest values of energy consumption and CO2 emissions were identified for future energetic and environmental optimisation.
- Food waste biorefinery : stability of an acidogenic fermentation system with carbon dioxide sequestration and electricity generationPublication . Ortigueira, Joana; Pacheco, Marta; Trancoso, Maria Ascensão; Farrancha, Pedro; Correia, Jorge; Silva, Carla M.; Moura, PatríciaABSTRACT: The present study focused on the integration of the non-sterile conversion of food waste (FW) into hydrogen (H2) through dark fermentation with the subsequent electricity generation in a proton-exchange membrane fuel cell (PEMFC), and the assessment of the global warming potential (GWP) of the process. The acidogenic conversion of FW performed in continuous operation for 16 days produced 45.6 ± 0.1 L H2 at an average H2 productivity of 6.1 ± 1.3 L L−1 d−1. Butyric and acetic acid were simultaneously produced at average concentrations of 3.6 ± 0.5 and 1.6 ± 0.3 g L −1, respectively. The carbon dioxide (CO2) from biogas product was sequestered by reaction with sodium hydroxide and the resulting H2-rich stream was fed to a PEMFC, producing 1.7 Wh L−1 H2. The process scale-up was simulated based on the bench-scale conversion yields and was used to assess the GWP. Two of the developed scenarios, which considered the reuse of the fermentation sludge as nitrogen source in the acidogenic fermentation, diminished the GWP emissions by 63.8% and 64.3% when compared to the default condition. In the best-case scenario, an annual average of 0.18 t of CO2 per t of FW separately collected was generated.
- Energetic and environmental evaluation of microalgae biomass fermentation for biohydrogen productionPublication . Ferreira, Ana F.; Ortigueira, Joana; Alves, Luís; Gouveia, Luisa; Moura, Patrícia; Silva, Carla M.This paper presents an energetic and environmental evaluation of the fermentative hydrogen production from the sugars of Scenedesmus obliquus biomass hydrolysate by Clostridium butyricum. The main purpose of this work was to evaluate the potential of H2 production and respective energy consumptions and CO2 emissions in the global fermentation process: hydrolysis of S. obliquus biomass, preparation of the fermentation medium, degasification and incubation. The scale-up to industrial production was not envisaged. Energy consumption and CO2 emissions estimations were based on SimaPro 7.1 software for the preparation of the fermentation medium and the use of degasification gas, nitrogen. The functional unit of energy consumption and CO2 emissions was defined as MJ and grams per 1 MJ of H2 produced, respectively. The electricity consumed in all hydrogen processes was assumed to be generated from the Portuguese electricity production mix. The hydrogen yield obtained in this work was 2.9 ± 0.3 mol H2/mol sugars in S. obliquus hydrolysate. Results show that this process of biological production of hydrogen consumed 281-405 MJ/MJH2 of energy and emitted 24-29 kgCO2/ MJH2. The fermentation stages with the highest values of energy consumption and CO2 emissions were identified for future energetic and environmental process optimisation.
- Third generation biohydrogen pProduction by Clostridium butyricum and adapted mixed cultures from Scenedesmus obliquus microalga biomassPublication . Ortigueira, Joana; Alves, Luís; Gouveia, Luisa; Moura, PatríciaScenedesmus obliquus biomass was used as a feedstock for comparing the biological production of hydrogen by two different types of anaerobic cultures: a heat-treated mixed culture from a wastewater treatment plant and Clostridium butyricum DSM 10702. The influence of the incubation temperature and the carbon source composition were evaluated in order to select the best production profile according to the characteristics of the microalgal biomass. C. butyricum showed a clear preference for monomeric sugars and starch, the latter being the major storage compound in microalgae. The highest H2 production reached by this strain from starch was 468 mL/g, whereas the mixed culture incubated at 37 C (LE37) produced 241 mL/g. When the mixed culture was incubated at 58 C (LE58), a significant increase in the H2 production occurred when xylose and xylan were used as carbon and energy source. The highest H2 yield reached by the LE37 culture or in co-culture with C. butyricum was 1.52 and 2.01 mol/mol of glucose equivalents, respectively. However, the ratio H2/CO2 (v/v) of the biogas produced in both cases was always lower than the one produced by the pure strain. In kinetic assays, C. butyricum attained 153.9 mL H2/L h from S. obliquus biomass within the first 24 h of incubation, with a H2 yield of 2.74 mol/mol of glucose equivalents. H2 production was accompanied mainly by acetate and butyrate as coproducts. In summary, C. butyricum demonstrated a clear supremacy for third generation bioH2 production from S. obliquus biomass.
- Lignin syngas bioconversion by Butyribacterium methylotrophicum: advancing towards an integrated biorefineryPublication . Pacheco, Marta; Pinto, Filomena; Ortigueira, Joana; Silva, Carla; Gírio, FranciscoABSTRACT: Hybrid bio-thermochemical based technologies have the potential to ensure greater feedstock flexibility for the production of bioenergy and bioproducts. This study focused on the bioconversion of syngas produced from low grade technical lignin to C-2-/C-4-carboxylic acids by Butyribacterium methylotrophicum. The effects of pH, medium supplementation and the use of crude syngas were analyzed. At pH 6.0, B. methylotrophicum consumed CO, CO2 and H-2 simultaneously up to 87 mol% of carbon fixation, and the supplementation of the medium with acetate increased the production of butyrate by 6.3 times. In long-term bioreactor experiments, B. methylotrophicum produced 38.3 and 51.1 mM acetic acid and 0.7 and 2.0 mM butyric acid from synthetic and lignin syngas, respectively. Carbon fixation reached 83 and 88 mol%, respectively. The lignin syngas conversion rate decreased from 13.3 to 0.9 NmL/h throughout the assay. The appearance of a grayish pellet and cell aggregates after approximately 220 h was indicative of tar deposition. Nevertheless, the stressed cells remained metabolically active and maintained acetate and butyrate production from lignin syngas. The challenge that impurities represent in the bioconversion of crude syngas has a direct impact on syngas cleaning requirements and operation costs, supporting the pursuit for more robust and versatile acetogens.
- Fermentation of biomass-derived syngas to ethanol and acetate by clostridium ljungdahliiPublication . Ortigueira, Joana; Pinto, Filomena; Gírio, Francisco; Moura, PatríciaIn the biochemical pathway of lignocellulosics conversion into fuels, a significant portion of biomass cannot be hydrolysed to fermentable sugars and remains as waste substrate that, due to its recalcitrance, is not converted to ethanol by microorganisms. In terms of product yield, this residual biomass represents renewable feedstock that is being wasted, which contradicts the target of 100% feedstock utilisation. The gasification of this biomass constitutes an alternative to circumvent this problem, as the produced synthesis gas (syngas) can be used as substrate for microorganisms that are able to convert CO, CO2 and H2 into important bulk chemicals and biofuels, such as ethanol, acetate and butanol [1,2]. Thus, syngas fermentation to ethanol and acetate can be regarded as a possible process to increase the overall product yield from lignocellulosic feedstock. Some advantages of fuels and chemicals production through syngas fermentation over metal catalyst conversion are the possibility of utilisation of the whole biomass regardless its quality, the independence of a fixed H2:CO ratio for the bioconversion process, a higher specificity of the microbial biocatalyst over chemical catalysts, and the bioreactor operation at ambient conditions [3]. However, syngas fermentation also presents several limitations, such as low yields and poor solubility of the gaseous substrate in the liquid phase. The objective of the present study was to evaluate C. ljungdahlii as microbial catalyst capable of fermenting syngas produced by gasification of spent solids obtained after lignocellulosic biomass saccharification and fermentation into ethanol. The heterotrophic and autotrophic growth of C. ljungdahlii were compared. Parameters such as bacterial growth, acetate and ethanol production, substrate consumption, and bioconversion yields were evaluated. In order to overcome the problem of gas diffusion in the liquid phase, fermentations were conducted at different total pressures
- Assessment of the adequacy of different Mediterranean waste biomass types for fermentative hydrogen production and the particular advantage of carob (Ceratonia siliqua L.) pulpPublication . Ortigueira, Joana; Silva, Carla M.; Moura, PatríciaABSTRACT: The conversion of agro-industrial byproducts, residues and microalgae, which are representative or adapted to the Mediterranean climate, to hydrogen (H2) by C. butyricum was compared. Five biomass types were selected: brewery’s spent grain (BSG), corn cobs (CC), carob pulp (CP), Spirogyra sp. (SP) and wheat straw (WS). The biomasses were delignified and/or saccharified, except for CP which was simply submitted to aqueous extraction, to obtain fermentable solutions with 56.2e168.4 g total sugars L 1. In small-scale comparative assays, the H2 production from SP, WS, CC, BSG and CP reached 37.3, 82.6, 126.5, 175.7 and 215.8 mL (g biomass) 1, respectively. The best fermentable substrate (CP) was tested in a pH-controlled batch fermentation. The H2 production rate was 204 mL (L h) 1 and a cumulative value of 3.9 L H2 L 1 was achieved, corresponding to a H2 production yield of 70.0 mL (g biomass) 1 or 1.6 mol (mol of glucose equivalents) 1. The experimental data were used to foresight a potential energy generation of 2.4 GWh per year in Portugal, from the use of CP as substrate for H2 production.
- Biohydrogen production from microalgal biomass: energy requirement, CO2 emissions and scale-up scenariosPublication . Ferreira, Ana F.; Ortigueira, Joana; Alves, Luís; Gouveia, Luisa; Moura, Patrícia; Silva, Carla M.
- Scenedesmus obliquus as feedstock for biohydrogen production by Enterobacter aerogenes and Clostridium butyricumPublication . Batista, Ana Paula; Moura, Patrícia; Marques, Paula; Ortigueira, Joana; Alves, Luís; Gouveia, LuisaHydrogen (H2) gas is seen as an ideal future energy carrier because it is easily converted into electricity in fuel cells, liberates a large amount of energy per unit mass, and generates no air pollutants. In this work, biological hydrogen (bioH2) was produced from the microalgal biomass of Scenedesmus obliquus which was used as a substrate for the fermentation by Enterobacter aerogenes ATCC 13048 and Clostridium butyricum DSM 10702. The bioH2 produced by each strain was assessed for different S. obliquus biomass concentrations, using both dried (5% moisture) and ‘‘wet’’ (69% moisture) biomass. The highest bioH2 production yields obtained were 57.6 mL H2/g VSalga from 2.5 galga/L by E. aerogenes and 113.1 mL H2/g VSalga from 50.0 galga/L by C. butyricum. The bioH2 production rates, and biogas purity attained by using the wet biomass as a fermentation substrate were similar or higher than those obtained with the dried microalga. This means that the drying step is not needed and therefore saves considerable energy as this is one of the highest energy demanding stages when using this feedstock in fermentations for biofuels production.
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