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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 Paula

Effluents 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.

2015Conference object

Open access

Food and fuel microalgae applications: insights from portuguese experience [Resumo]

Publication . Batista, Ana Paula; Nobre, B. P.; Oliveira, Ana Cristina; Passarinho, Paula; Marques, Paula; Ribeiro, Belina; Raymundo, Anabela; Sousa, Isabel; Gouveia, Luisa; Marques, Isabel Paula

Microalgae have a wide range of application fields, from food to fuels, to pharmaceuticals & fine chemicals, aquaculture and environmental bioremediation, among others. Spirulina and Chlorella have been used as food sources since ancient times, due to their high and balanced nutritional value. Our research group in Lisbon has developed a range of food products (emulsions, gelled desserts, biscuits and pastas) enriched with freshwater and marine microalgae (Spirulina, Chlorella, Haematococcus, Isochrysis and Diacronema). The developed products presented attractive and stable colours, high resistance to oxidation and enhanced rheological properties. Some of these products will be prepared at the Post-Congress Course “Functional Foods Development” at the University of Antofagasta. More recently, a great interest has arisen on using microalgae for biofuel production. The same group has also been exploring several marine and freshwater species for biofuel production (e.g., biodiesel, bioethanol, biohydrogen and biomethane) within a biorefinery approach, in order to obtain high and low-value co-products using integral biomass maximizing the energy revenue. Namely, supercritical fluid extraction of Nannochloropsis sp. allowed the recovery of valuable carotenoids and lipids, prior to bioH2 production through dark fermentation of the residual biomass. Also, Scenedesmus obliquus residues after sugars (for bioethanol) and lipids (for biodiesel) extraction has been anaerobically digested attaining high biomethane yields. Regarding sustainability issues, the current trend of our group is now focused on using liquid effluents and high CO2 levels for low cost microalgae growth, contributing to a lower water demand, primary energy consumption and global warming potential by reducing the need for potable water and fertilizers (P, N) and increasing CO2 mitigation. Microalgae biomass has been successfully used for urban wastewater treatment with subsequent bioH2 production, in a biorefinery approach. Presently, ammonium-rich raw effluents from piggeries and poultry industry are being effectively used for microalgae growth avoiding any pre-treatment step.

2015Conference object

Open access

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

2015Conference object

Open access

Low-energy harvesting and drying methods for Spirulina maxima: effect on phycocyanin content [Resumo]

Publication . Batista, Ana Paula; Monteiro, Ana Carina; Loureiro, David; Gouveia, Luisa; Sousa, Isabel

2015Conference object

Open access

Fermentative hydrogen production from microalgal biomass by a single strain of bacterium Enterobacter aerogenes: effect of operational conditions and fermentation kinetics

Publication . Batista, Ana Paula; Gouveia, Luisa; Marques, Paula

ABSTRACT: Biohydrogen production through dark fermentation is a promising technology for generating renewable energy, while using microalgal biomass as a third generation feedstock can further increase the sustainability of the process. In the present study, Scenedesmus obliquus was used as model microalga substrate for studying the impact of operational parameters in batch dark fermentation trials using a strain of Enterobacter aerogenes bacteria. (i) The initial gas-liquid ratio in the bioreactor (from 13 to 8.2) was tested, resulting in higher bioH(2) yields for ratios above 5. (ii) Different bacterial growth, inoculation procedures and fermentation media were tested in combined experiments. The best conditions were chosen by maximising bioH(2) yield and minimising production time and costs. (iii) The autoclave sterilization effect on sugar extraction and bioH(2) yield was tested for different microalga concentrations (2.5-50 g/L) with best results attained for 2.5 g/L (81.2% extraction yield, 40.9 mL H-2/g alga). For the best operational conditions, fermentation kinetics were monitored and adjusted to the Modified Gompertz model, with t(95) (time required for bioH(2) production to attain 95% of the maximum yield) below 4.5 h. The maximum hydrogen production was higher when using wet algal biomass enabling the energy Consuming biomass drying step to be skipped.

2018Journal article

Open access