Title: CO2 utilization in the production of biomass and biocompounds by three different microalgae
Authors: Joana Assuncao, Ana Paula Batista, Joao Manoel, Teresa Lopes da Silva, Paula Marques, Alberto Reis, Luisa Gouveia
Publication: Eng. Life Sci. 2017, 17, 1126-1135
Published: 24 July 2017
The atmospheric CO2 increase is considered the main cause of global warming. Microalgae are photosynthetic microorganisms that can help in CO2 mitigation and at the same time produce value‐added compounds. In this study, Scenedesmus obliquus, Chlorella vulgaris, and Chlorella protothecoides were cultivated under 0.035 (air), 5 and 10% (v/v) of CO2 concentrations in air to evaluate the performance of the microalgae in terms of kinetic growth parameters, theoretical CO2 biofixation rate, and biomass composition. Among the microalgae studied, S. obliquus presented the highest values of specific growth rate (μ = 1.28 d−1), maximum productivities (Pmax = 0.28 g L−1d−1), and theoretical CO2 biofixation rates (0.56 g L−1d−1) at 10% CO2. The highest oil content was found at 5% CO2, and the fatty acid profile was not influenced by the concentration of CO2 in the inflow gas mixture and was in compliance with EN 14214, being suitable for biodiesel purposes. The impact of the CO2 on S. obliquus cells’ viability/cell membrane integrity evaluated by the in‐line flow cytometry is quite innovative and fast, and revealed that 86.4% of the cells were damaged/permeabilized in cultures without the addition of CO2.
Title: Evaluation of Marine Microalga Diacronema vlkianum Biomass Fatty Acid
Assimilation in Wistar Rats
Authors: Cristina de Mello-Sampayo, Angela Paterna, Ambra Polizzi, Diana Duarte, Irineu Batista, Rui Pinto, Patrícia Gonçalves, Anabela Raymundo, Ana P. Batista, Luísa Gouveia, Beatriz Silva-Lima and Narcisa M. Bandarra
Publication: Molecules 2017, 22(7), 1097
Published: 1 July 2017
Diacronema vlkianum is a marine microalgae for which supposed health promoting effects have been claimed based on its phytochemical composition. The potential use of its biomass as health ingredient, including detox-shakes, and the lack of bioavailability studies were the main concerns. In order to evaluate the microalgae-biomass assimilation and its health-benefits, single-dose (CD1-mice) studies were followed by 66-days repeated-dose study in Wistar rats with the highest tested single-dose of microalgae equivalent to 101 mg/kg eicosapentaenoic acid + docosahexaenoic acid (EPA+DHA). Microalgae-supplementation modulated EPA and docosapentaenoic acid enrichment at arachidonic acid content expenditure in erythrocytes and liver, while increasing EPA content of heart and adipose tissues of rats. Those fatty acid (FA) changes confirmed the D. vlkianum-biomass FA assimilation. The principal component analyses discriminated brain from other tissues, which formed two other groups (erythrocytes, liver, and heart separated from kidney and adipose tissues), pointing to a distinct signature of FA deposition for the brain and for the other organs. The improved serum lipid profile, omega-3 index and erythrocyte plasticity support the cardiovascular benefits of D. vlkianum. These results bolster the potential of D. vlkianum-biomass to become a “heart-healthy” food supplement providing a safe and renewable source of bioavailable omega-3 FA.
Title: Isolation of a euryhaline microalgal strain, Tetraselmis sp. CTP4, as a robust feedstock for biodiesel production
Authors: Hugo Pereira, Katkam N. Gangadhar, Peter S. C. Schulze, Tamára Santos, Carolina Bruno de Sousa, Lisa M. Schueler, Luísa Custódio, F. Xavier Malcata, Luísa Gouveia, João C. S. Varela & Luísa Barreira
Publication: Scientific Reports volume 6, Article number: 35663 (2016)
Published: 21 October 2016
Bioprospecting for novel microalgal strains is key to improving the feasibility of microalgae-derived biodiesel production. Tetraselmis sp. CTP4 (Chlorophyta, Chlorodendrophyceae) was isolated using fluorescence activated cell sorting (FACS) in order to screen novel lipid-rich microalgae. CTP4 is a robust, euryhaline strain able to grow in seawater growth medium as well as in non-sterile urban wastewater. Because of its large cell size (9–22 μm), CTP4 settles down after a six-hour sedimentation step. This leads to a medium removal efficiency of 80%, allowing a significant decrease of biomass dewatering costs. Using a two-stage system, a 3-fold increase in lipid content (up to 33% of DW) and a 2-fold enhancement in lipid productivity (up to 52.1 mg L−1 d−1) were observed upon exposure to nutrient depletion for 7 days. The biodiesel synthesized from the lipids of CTP4 contained high levels of oleic acid (25.67% of total fatty acids content) and minor amounts of polyunsaturated fatty acids with ≥4 double bonds (<1%). As a result, this biofuel complies with most of the European (EN14214) and American (ASTM D6751) specifications, which commonly used microalgal feedstocks are usually unable to meet. In conclusion, Tetraselmis sp. CTP4 displays promising features as feedstock with lower downstream processing costs for biomass dewatering and biodiesel refining.
Title: Effect of Arthrospira platensis on the Shelf Life, Sensorial and Rheological Properties of strudel
Authors: KIANOUSH KHOSRAVI-DARANI, ZAHRA GHOLAMI, LUISA GOUVEIA
Publication: Romanian Biotechnological Letters 22/1 (2017) 12250–12258
Arthrospira platensis microalga is widely used in the food industry due to its nutritional value such as having high protein content, vitamins, essential amino acids, minerals and antimicrobial properties that inhibit the growth of mold and yeast. This study aimed to evaluate the effect of the addition of dried microalga at different levels (0, 0.5, 1 and 1.5% w/w) on the technological, sensorial, and rheological properties (texture and
color), as well as on the stability and the nutritional value of strudel. Results showed that the protein content of the enriched strudel was higher than control (p< 0.05) while its peroxide value reduced (p<0.01). Colorimetric analysis also showed that within 45 days, the color stability of enriched strudel samples was higher than control
(p<0.05). Results from sensorial analysis done by 10 panelists indicated that addition of powdered Arthrospira results in a brittle strudel and 0.5 and 1% fortification achieved the most popular preferences. The overall acceptance results showed that the best strudel can be obtained by adding 0.5 to 1 % Arthrospira platensis, which in addition to the improvement of the sensorial and rheological properties, also has antimicrobial properties that inhibit the growth of yeasts and molds.
Title: Scenedesmus obliquus mediated brewery wastewater remediation and
CO2 biofixation for green energy purposes
Authors: Alice Ferreira, Belina Ribeiro, Paula A.S.S. Marques, Ana F. Ferreira, Ana Paula Dias, Helena M. Pinheiro, Alberto Reis, Luisa Gouveia
Publication: Journal of Cleaner Production 165 (2017) 1316–1327
Published: Available online 31 July 2017
Microalgae can be used for wastewater bioremediation with simultaneous CO2 biofixation producing valuable biomass.
Wastewater from a brewery was treated using the Scenedesmus obliquus microalga in bubble-column photobioreactors (PBRs). The PBRs were fed with ambient air and the effect of a 10% (v/v) brewery CO2 supplement was studied. The PBRs were inoculated and a range of mean hydraulic residence time (HRT) values were tested (2.1-10.4 days). The maximum ash-free dry weight (AFDW) biomass productivity was obtained for a HRT of 3.5 days (0.29 d-1 dilution rate; 0.2 g L-1 d-1 (in terms of AFDW). The highest pollutant removal efficiencies were 92.9 and 88.5% for ammonia and total nitrogen, respectively, 40.8% for phosphorus, and 61.9% for COD. Except a dilution rate of 0.48 d-1 trial, the treated wastewater always met the Portuguese legislation quality standard for discharge into natural water bodies. Aiming to simultaneously maximize biomass volumetric productivity, CO2 biofixation rate and wastewater treatment efficiency, while minimizing residence time, 0.29 d-1 represents the optimal dilution rate value.
The potential of the produced Scenedesmus obliquus biomass was evaluated for the generation of biohydrogen through dark fermentation with Enterobacter aerogenes, and of bio-oil, bio-char and bio-gas through a pyrolysis process. The yields obtained were 67.1 mL H2 g-1 (in terms of volatile solids – VS) for bioH2 and 64, 30 and 6% for bio-oil, bio-char and bio-gas, respectively (dry mass content (%) calculated over freeze dryer biomass basis).
Title: Microalgae biomass as an alternative ingredient in cookies: Sensory, physical and chemical properties, antioxidant activity and in vitro digestibility
Authors: Ana Paula Batista, Alberto Niccolai, Patrícia Fradinho, Solange Fragoso, Ivana Bursic, Liliana Rodolfi, Natascia Biondi, Mario R. Tredici, Isabel Sousa, Anabela Raymundo
Publication: Algal Research 26 (2017) 161–171
Published: 24 July 2017
Microalgae can be regarded as an alternative and promising food ingredient due to their nutritional composition, richness in bioactive compounds, and because they are considered a sustainable protein source for the future. The aim of this work was to evaluate microalgae (Arthrospira platensis F & M-C256, Chlorella vulgaris Allma, Tetraselmis suecica F & M-M33 and Phaeodactylum tricornutum F & M-M40) as innovative ingredients to enhance functional properties of cookies. Two biomass levels were tested and compared to control: 2% (w/w) and 6% (w/w), to provide high levels of algae-bioactives. The cookies sensory and physical properties were evaluated during eight weeks showing high color and texture stability. Cookies prepared with A. platensis and C. vulgaris presented significantly (p < 0.05) higher protein content compared to the control, and by sensory analysis A. platensis cookies were preferred. Besides, A. platensis also provided a structuring effect in terms of cookies texture. All microalgae-based cookies showed significantly higher (p < 0.05) total phenolic content and in vitro antioxidant capacity compared to the control. No significant difference (p < 0.05) in in vitro digestibility between microalgae cookies and the control was found.
Title: Photodegradation and sorption govern tetracycline removal during wastewater treatment in algal ponds
Authors: Norvill Z, Toledo-Cervantes A, Blanco S, Shilton A, Guieysse B, Muñoz R
Publication: Bioresource Technology, Volume 232, Pages 35–43
Published: May 2017
The degradation of the antibiotic tetracycline, supplied at 100 µg L−1 in domestic wastewater, was studied in an outdoor, pilot scale, high rate algal pond (HRAP). Effective operation was demonstrated with the biomass concentration and the chemical oxygen demand removal efficiency averaging 1.2 ± 0.1 gTSS L−1 and 80 ± 4%, respectively, across all operational periods. Tetracycline removal exceeded 93% and 99% when the HRAP was operated at hydraulic retention times of 4 and 7 days, respectively. Batch tests and pulse testing during HRAP operation repeatedly evidenced the significance of photodegradation as a removal mechanism. Sorption dominated tetracycline removal during the night, but accounted for less than 6% of the total pollutant removal based on sorbed tetracycline extracted from biomass. Overall, these results provide the first demonstration of efficient antibiotic removal, occurring mainly via indirect photodegradation, during relevant HRAP operation (low pollutant concentration, domestic wastewater and natural sunlight).
Title: A study of photosynthetic biogas upgrading based on a high rate algal pond under alkaline conditions: Influence of the illumination regime
Authors: Franco M, Alcántara C, Noyola A, Muñoz R, Gonzalez-Sanchez A.
Publication: Science of The Total Environment, Volume 592, Pages 419–425
Published: 15 August 2017
Microalgal-bacterial processes have emerged as environmental friendly systems for the cost-effective treatment of anaerobic effluents such as biogas and nutrients-laden digestates. Environmental parameters such as temperature, irradiation, nutrient concentration and pH effect the performance of the systems. In this paper, the potential of a microalgal-bacterial photobioreactor operated under high pH (≈ 9.5) and high alkalinity to convert biogas into biomethane was evaluated. The influence of the illumination regime (continuous light supply vs 12 h/12 h light/dark cycles) on the synthetic biogas upgrading efficiency, biomass productivity and nutrient removal efficiency was assessed in a High-Rate Algal Pond interconnected to a biogas absorption bubble column. No significant differences in the removal efficiency of CO2 and H2S (91.5 ± 2% and 99.5% ± 0.5, respectively) were recorded regardless of the illumination regime. The high fluctuations of the dissolved oxygen concentration during operation under light/dark cycles allowed to evaluate the specific growth rate and the specific partial degradation rate of the microalgae biomass by photosynthesis and respiration, respectively. The respiration reduced the net microalgae biomass productivity under light/dark cycles compared with process operation under the continuous light supply.
Title: Influence of the gas-liquid flow configuration in the absorption column on photosynthetic biogas upgrading in algal-bacterial photobioreactors
Authors: Toledo-Cervantes A, Madrid-Chirinos C, Cantera S, Lebrero R, Muñoz R
Publication: Bioresource Technology, Volume 225, Pages 336–342
Published: February 2017
The potential of an algal-bacterial system consisting of a high rate algal pond (HRAP) interconnected to an absorption column (AC) via recirculation of the cultivation broth for the upgrading of biogas and digestate was investigated. The influence of the gas-liquid flow configuration in the AC on the photosynthetic biogas upgrading process was assessed. AC operation in a co-current configuration enabled to maintain a biomass productivity of 15 g m−2 d−1, while during counter-current operation biomass productivity decreased to 8.7 ± 0.5 g m−2 d−1 as a result of trace metal limitation. A bio-methane composition complying with most international regulatory limits for injection into natural gas grids was obtained regardless of the gas-liquid flow configuration. Furthermore, the influence of the recycling liquid to biogas flowrate (L/G) ratio on bio-methane quality was assessed under both operational configurations obtaining the best composition at an L/G ratio of 0.5 and co-current flow operation.
Title: Toluene biodegradation in an algal-bacterial airlift photobioreactor: Influence of the biomass concentration and of the presence of an organic phase
Authors: Lebrero R, Angeles R, Perez R, Muñoz R
Publication: Journal of Environmental Management, Volume 183, Part 3, Pages 585–593
Published: 1 December 2016
The potential of algal-bacterial symbiosis for off-gas abatement was investigated for the first time by comparatively evaluating the performance of a bacterial (CB) and an algal-bacterial (PB) airlift bioreactors during the treatment of a 6 g m−3 toluene laden air emission. The influence of biomass concentration and of the addition of a non-aqueous phase was also investigated. A poor and fluctuating performance was recorded during the initial stages of the experiment, which was attributed to the low biomass concentration present in both reactors and to the accumulation of toxic metabolites. In this sense, an increase in the dilution rate from 0.23 to 0.45 d−1 and in biomass concentration from ∼1 to ∼5 g L−1 resulted in elimination capacities (ECs) of 300 g m−3h−1 (corresponding to removal efficiencies ∼ 90%). Microalgae activity allowed for a reduction in the emitted CO2 and an increase in dissolved O2 concentration in the PB. However, excess biomass growth over 11 g L−1 hindered light penetration and severely decreased photosynthetic activity. The addition of silicone oil at 20% (on a volume basis) stabilized system performance, leading to dissolved O2 concentrations of 7 mg L−1 and steady ECs of 320 g m−3 h−1 in the PB. The ECs here recorded were considerably higher than those previously reported in toluene-degrading bioreactors. Finally, microbial population analysis by DGGE-sequencing demonstrated the differential specialization of the microbial community in both reactors, likely resulting in different toluene degradation pathways and metabolites production.
Title: Saccharification of microalgae biomass obtained from wastewater treatment by enzymatic hydrolysis. Effect of alkaline-peroxide pretreatment
Authors: Martin-Juárez J, Lorenzo-Hernando A, Muñoz-Torre R, Blanco-Lanza S, Bolado-Rodríguez S
Publication: Bioresource Technology, Volume 218, Pages 265–271
Published: October 2016
An enzymatic method for the carbohydrate hydrolysis of different microalgae biomass cultivated in domestic (DWB) and pig manure (PMWB) wastewaters, at different storage conditions (fresh, freeze-dried and reconstituted), was evaluated. The DWB provided sugars yields between 40 and 63%, although low xylose yields (< 23.5%). Approximately 2% of this biomass was converted to byproducts as succinic, acetic and formic acids. For PMWB, a high fraction of the sugars (up to 87%) was extracted, but mainly converted into acetic, butyric and formic acids, which was attributed to the bacterial action. In addition, the performance of an alkaline-peroxide pretreatment, conducted for 1 h, 50 °C and H2O2 concentrations from 1 to 7.5% (w/w), was essayed. The hydrolysis of pretreated microalgae supported a wide range of sugars extraction for DWB (55–90%), and 100% for PMWB. Nevertheless, a large fraction of these sugars (∼30% for DWB and 100% for PMWB) was transformed to byproducts.
Title: The Diatom Staurosirella pinnata for Photoactive Material Production
Authors: Roberta De Angelis, Sonia Melino, Paolo Prosposito, Mauro Casalboni, Francesca Romana Lamastra, Francesca Nanni, Laura Bruno, Roberta Congestri
Publication: PLoS ONE 11(11): e0165571
Published: November 9, 2016
A native isolate of the colonial benthic diatom Staurosirella pinnata was cultivated for biosilica production. The silicified cell walls (frustules) were used as a source of homogeneous and structurally predictable porous biosilica for dye trapping and random laser applications. This was coupled with the extraction of lipids from biomass showing potential to fabricate photoactive composite materials sustainably. The strain was selected for its ease of growth in culture and harvesting. Biosilica and lipids were obtained at the end of growth in indoor photobioreactors. Frustules were structurally characterized microscopically and their chemistry analyzed with Fourier Transform Infrared Spectroscopy. Frustule capacity of binding laser dyes was evaluated on a set of frustules/Rhodamine B (Rho B) solutions and with respect to silicon dioxide and diatomite by Fluorescence Spectroscopy demonstrating a high affinity for the organic dye. The effect of dye trapping property in conveying Rho B emission to frustules, with enhancement of scattering events, was analyzed on Rho B doped polyacrylamide gels filled or not with frustules. Amplified spontaneous emission was recorded at increasing pump power indicating the onset of a random laser effect in frustule filled gels at lower power threshold compared to unfilled matrices.
Title: Microalga Nannochloropsis sp. biomass for biodiesel production: conventional (cell disruption) and in situ transesterification
Authors: Gouveia, L.; Janelas, J.; Torpecelo, A.; Oliveira, A.C.
Publication: Journal of Marine Biology & Oceanography
Published: April 19, 2016
The potential of Nannochloropsis sp. microalga to biodiesel production was assessed. The work deals with the optimization of the cell disruption, a required step when the lipid extraction followed by the transesterification reaction is the option to produce biodiesel, as well as the optimization of the reaction parameters (catalyst, alcohol, temperature and time) of the in situ transesterification (direct conversion of the saponifiable lipids into FAME – fatty acid metyl esters, usually called as biodiesel, in one step). The cell rupture of wet and dried biomass (by oven and freezedryer) using different methods (physical – coffee grinder and ball-mill; and thermodynamic – microwaves and autoclave) was evaluated. The highest lipid recovery (42.4 ± 0.2% g of lipids /g of oven dried biomass) was attained from the oven dried biomass pretreated in a coffee grinder followed by a ball milling. The microalgal oil quality (fatty acid profile, acid value and iodine value) was determined and was not influenced by the biomass state (oven or freeze-dried) nor by the cell rupture method, being mainly composed of palmitic (C16:0), palmitoleic (C16:1) and oleic (C18:1) acids. The linoleic acid (C18:3) content is quite low (< 0.35% w/w) which results in a high quality biodiesel in terms of this parameter. The viability of the in situ transesterification, in order to reduce technological challenges, energy, time, environmental negative impacts and costs of the traditional processes, was studied and optimized The most favourable conditions were found to be 3.16 g of methanol / 100 g of dry biomass, 1.2% v/v of catalyst (H2SO4), for 6 h at 50°C, which allows of 95% esters formation. In terms of the cell rupture, the coffee grinder followed by the ball mill, proved again, to be the most efficient process, promoting an increase in the transesterification reaction rate.
Title: Microalgae biomass production using wastewater: treatment and costs. Scaleup considerations
Authors: Gouveia, L.; G raça, S.; Sousa, C.; Ambrosano, L; Ribeiro, B.; Botrel E.P.; Neto, P.C.; Ferreira, Ana F.; Silva, CM.
Publication: Algal Research 16, 167–176
Published: June 2016
This work is part of a LIFE project to treat urban wastewater from Águas da Figueira (AdF, Figueira da Foz, PT) using a vertical tubular photobioreactor (PBR) prototype (150 L), to be scaled up and integrated in a waste water treatment plant (WWTP). The PBR was inoculated with three different microalgae: Chlorella vulgaris (Cv), Scenedesmus obliquus (Sc) and Consortium C (ConsC), isolated from the effluent. The study intends to find the best microalga in terms of wastewater remediation, biomass productivity and quality, for further uses, such as biofuel, biofertilizer and bioplastic production.
Title: Capturing biodiversity: linking a cyanobacteria culture collection to the “scratchpads” virtual research environment enhances biodiversity knowledge
Authors: Spyros Gkelis, Manthos Panou
Publication: Biodiversity Data Journal 4: e7965
Published: 06 Apr 2016 (Open-Access)
Currently, cyanobacterial diversity is examined using a polyphasic approach by assessing morphological and molecular data (Komárek 2015). However, the comparison of morphological and genetic data is sometimes hindered by the lack of cultures of several cyanobacterial morphospecies and inadequate morphological data of sequenced strains (Rajaniemi et al. 2005). Furthermore, in order to evaluate the phenotypic plasticity within defined taxa, the variability observed in cultures has to be compared to the range in natural variation (Komárek and Mareš 2012). Thus, new tools are needed to aggregate, link and process data in a meaningful way, in order to properly study and understand cyanodiversity.
An online database on cyanobacteria has been created, namely the Cyanobacteria culture collection (CCC) (http://cyanobacteria.myspecies.info/) using as case studies cyanobacterial strains isolated from lakes of Greece, which are part of the AUTH culture collection (School of Biology, Aristotle University of Thessaloniki). The database hosts, for the first time, information and data such as morphology/morphometry, biogeography, phylogeny, microphotographs, distribution maps, toxicology and biochemical traits of the strains. All this data are structured managed, and presented online and are publicly accessible with a recently developed tool, namely “Scratchpads”, a taxon-centric virtual research environment allowing browsing the taxonomic classification and retrieving various kinds of relevant information for each taxon.
cyanobacteria, database, Scratchpads, taxonomy, morphology, phylogeny, biodiversity informatics
Title: EUALGAE: Microalgae proteins and ingredients
Author: Maria Hayes, Teagasc Food Research Centre, Ashtown
Publication: TResearch, Volume 11: Number 1. Spring 2016, 32‐33.
Authors: Cristina Gonzalez-Fernandez, Bruno Sialve, Beatriz Molinuevo-Salces
Publication: Bioresource Technology, 2015, 198, 896‐906.
• Microalgae biomass has a huge potential as feedstock for biogas production.
• Novel pretreatments, reactor designs and operation parameters are addressed.
• The microbial community carrying out anaerobic digestion is reviewed.
• Research on intermediate compounds exploitation is discussed.
• Integration of microalgae culture and anaerobic digestion is outlined.