Loading...
35 results
Search Results
Now showing 1 - 10 of 35
- Scenedesmus obliquus in poultry wastewater bioremediationPublication . Oliveira, Ana Cristina; Barata, Ana; Batista, Ana Paula; Gouveia, LuisaABSTRACT: Wastewater biological treatment with microalgae can be an effective technology, removing nutrients and other contaminants while reducing chemical oxygen demand. This can be particularly interesting for the meat producing industry which produces large volumes of wastewater from the slaughtering of animals and cleaning of their facilities. The main purpose of this research was the treatment of poultry wastewater using Scenedesmus obliquus in an economical and environmentally sustainable way. Two wastewaters were collected from a Portuguese poultry slaughterhouse (poultry raw - PR and poultry flocculated - PF) and the bioremediation was evaluated. The performance of microalga biomass growth and biochemical composition were assessed for two illumination sources (fluorescent vs LEDs). S. obliquus achieved positive results when grown in highly contaminated agro-industrial wastewater from the poultry industry, independently of the light source. The wastewater bioremediation revealed results higher than 97% for both ammonium and phosphate removal efficiency, for a cultivation time of 13 days. The saponifiable matter obtained from the biomass of the microalga cultures was, on average, 11% and 27% (m/malga) with PR and PF wastewater, respectively. In opposition, higher sugar content was obtained from microalgae biomass grown in PR wastewater (average 34% m/malga) in comparison to PF wastewater (average 23% m/malga), independently of the illumination source. Therefore, biomass obtained with PR wastewater will be more appropriate as a raw material for bioethanol/biohydrogen production (higher sugar content) while biomass produced in PF wastewater will have a similar potential as feedstock for both biodiesel and bioethanol/biohydrogen production (similar lipid and sugar content).
- Admissibility Grid to Support the Decision for the Preferential Routing of Portuguese Endogenous Waste Biomass for the Production of Biogas, Advanced Biofuels, Electricity and HeatPublication . Crujeira, Teresa; Trancoso, Maria Ascensão; Eusebio, Ana; Oliveira, Ana Cristina; Passarinho, Paula; Abreu, Mariana; Marques, Isabel Paula; Marques, Paula; Marques, Susana; Albergaria, Helena; Pinto, Filomena; Costa, Paula; Andre, Rui N.; Girio, Francisco; Moura, PatríciaABSTRACT: A methodology was developed to assess the allocation of different types of endogenous waste biomass to eight technologies for producing electricity, heat, biogas and advanced biofuels. It was based on the identification of key physicochemical parameters for each conversion process and the definition of limit values for each parameter, applied to two different matrices of waste biomass. This enabled the creation of one Admissibility Grid with target values per type of waste biomass and conversion technology, applicable to a decision process in the routing to energy production. The construction of the grid was based on the evaluation of 24 types of waste biomass, corresponding to 48 sets of samples tested, for which a detailed physicochemical characterization and an admissibility assessment were made. The samples were collected from Municipal Solid Waste treatment facilities, sewage sludges, agro-industrial companies, poultry farms, and pulp and paper industries. The conversion technologies and energy products considered were (trans)esterification to fatty acid methyl esters, anaerobic digestion to methane, fermentation to bioethanol, dark fermentation to biohydrogen, combustion to electricity and heat, gasification to syngas, and pyrolysis and hydrothermal liquefaction to bio-oils. The validation of the Admissibility Grid was based on the determination of conversion rates and product yields over 23 case studies that were selected according to the best combinations of waste biomass type versus technological solution and energy product.
- 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.
- Moesziomyces spp. cultivation using cheese whey: new yeast extract-free media, beta-galactosidase biosynthesis and mannosylerythritol lipids productionPublication . Nascimento, Miguel Figueiredo; Barreiros, Ricardo; Oliveira, Ana Cristina; Ferreira, Frederico Castelo; Faria, Nuno TorresABSTRACT: Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a wide range of potential applications. However, high production costs, low productivity and unsatisfactory scale-up production have hampered commercial adoption. Herein, we report for the first time the beta-galactosidase production by Moesziomyces spp. from different sugars (D-galactose, D-glucose and D-lactose), with D-galactose being the best beta-galactosidase inducer, with 11.2 and 63.1 IU/mg(biomass), for Moesziomyces aphidis 5535(T) and Moesziomyces antarcticus 5048(T), respectively. The production of this enzyme allows to break down D-lactose and thus to produce MEL directly from D-lactose or cheese whey (a cheese industry by-product). Remarkably, when CW was used as sole media component (carbon and mineral source), in combination with waste frying oil, MEL productivities were very close (1.40 and 1.31 g(MEL)/L/day) to the ones obtained with optimized medium containing yeast extract (1.92 and 1.50 g(MEL)/g(susbtrate)), both for M. antarcticus and M. aphidis. The low-cost, facile and efficient process which generates large amounts of MELs potentiates its industrialization.
- Implementation of sustainability criteria for biofuels and bioliquids in PortugalPublication . Matos, Cristina T.; Gírio, Francisco; Oliveira, Ana Cristina; Silva, Luís; Lukasik, Rafal M.
- Biocombustíveis. Um contributo para o sector dos transportesPublication . Oliveira, Ana Cristina
- Life-cycle assessment of microalgae biodiesel: a reviewPublication . Figueiredo, Filipa; Garcia, Rita; Gonçalves, Margarida S.; Castanheira, Érica; Malça, João; Oliveira, Ana Cristina; Matos, Cristina T.; Freire, FaustoMicroalgae are an attractive way to produce biofuels due to the ability to accumulate lipids and very high photosynthetic yields. This article presents a review of life-cycle assessment studies of microalgae biodiesel production, including an analysis of modeling choices and assumptions. A high variation in GHG emissions (between -0.75 and 2.9 kg CO2eq MJ-1) was found and the main causes were investigated, namely modeling choices (e.g. the approach used to deal with multifunctionality), and a high parameter uncertainty in microalgae cultivation, harvesting and oil extraction processes.
- Life cycle assessment of advanced bioethanol production from pulp and paper sludgePublication . Sebastião, Diogo; Gonçalves, Margarida S.; Marques, Susana; Fonseca, César; Gírio, Francisco; Oliveira, Ana Cristina; Matos, Cristina T.This work evaluates the environmental performance of using pulp and paper sludge as feedstock for the production of second generation ethanol. An ethanol plant for converting 5400 tons of dry sludge/year was modelled and evaluated using a cradle-to-gate life cycle assessment approach. The sludge is a burden for pulp and paper mills that is mainly disposed in landfilling. The studied system allows for the valorisation of the waste, which due to its high polysaccharide content is a valuable feedstock for bioethanol production. Eleven impact categories were analysed and the results showed that enzymatic hydrolysis and neutralisation of the CaCO3 are the environmental hotspots of the system contributing up to 85% to the overall impacts. Two optimisation scenarios were evaluated: (1) using a reduced HCl amount in the neutralisation stage and (2) co-fermentation of xylose and glucose, for maximal ethanol yield. Both scenarios displayed significant environmental impact improvements.
- Brazilian castor oil as raw material for biodiesel productionPublication . Lages, Cléia; Araújo, Eduardo; Oliveira, Ana Cristina
- Biocombustíveis: uma oportunidade ou um problema para PortugalPublication . Gírio, Francisco; Lukasik, Rafal M.; Matos, Cristina T.; Oliveira, Ana Cristina; Silva, LuísApresenta-se nesta curta comunicação a problemática referente à introdução dos biocombustíveis nos transportes em Portugal na sequência da transposição para a legislação nacional das diferentes diretivas europeias (2003 e 2009). A produção de biocombustíveis em território nacional tem vindo a aumentar na sequência da política nacional de promoção dos mesmos embora as matérias-primas utilizadas (oleaginosas) sejam praticamente todas importadas com exceção do uso de matérias residuais. Particular atenção é dedicada aos dois critérios de sustentabilidade obrigatórios para que um dado biocombustível seja considerado “produzido de forma sustentável”, abordando-se ainda a problemática das alterações indiretas do uso da terra (ILUC) na sequência da recente proposta da Comissão Europeia em rever a atual diretiva nesta matéria.