Repeated nitrogen starvation doesn't affect lipid productivity of Chlorococcum littorale

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Cell diameter doesn't affect lipid productivity of Chlorococcum littorale

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Sorting cells of the microalga Chlorococcum littorale with increased triacylglycerol productivity

Despite extensive research in the last decades, microalgae are still only economically feasible for high valued markets. Strain improvement is a strategy to increase productivities, hence reducing costs. In this work, we focus on microalgae selection: taking advantage of the natural biological variability of species to select variations based on desired characteristics. We focused on triacylglycerol (TAG), which have applications ranging from biodiesel to high-value omega-3 fatty-acids. Hence, we demonstrated a strategy to sort microalgae cells with increased TAG productivity

Production of exopolysaccharide by Botryococcus braunii CCALA 778 under laboratory simulated Mediterranean climate conditions

This work aims at optimizing biomass and exopolysaccharide productivities of Botryococcus braunii CCALA 778 grown under simulated Mediterranean climate conditions. The effect of temperature and light irradiance on biomass and exopolysaccharide productivity were studied. Our results show that light:dark cycles lead to higher biomass and sugar productivities in comparison to continuous illumination. The optimal temperature of Botryococcus braunii CCALA 778 ranges from 23 to 26 °C, although it is tolerant to low temperatures (4 °C). The highest exopolysaccharide productivity (0.29 ± 0.05 g exopolysaccharide L− 1 day−1) was obtained during high light irradiance (simulating a summer day) and temperature controlled at 26 °C

Techno-economic analysis of microalgae production for aquafeed in Norway

The sustainability of the aquaculture sector depends mainly on the search for alternative sources to fishmeal and fish oil, one of which is microalgae. However, there are few feasibility studies of the microalgae process chain. This work aimed to address this gap through a TEA of microalgae (Phaeodactylum tricornutum) production. The TEA combines process modelling, engineering design and economic evaluation. As a result, different projections are obtained, yielding the breakdown of capital investment and operating costs. The study is based on pilot-scale experimental results using tubular PBR in Norway. This TEA shows that 29.48 t of biomass per ha of facility and year would be a real productivity. At PBR scales of 1 and 100 ha, microalgae could be produced for 108.26 or 44 €/kg DW of harvested biomass respectively. Artificial light is indispensable for microalgae production in Norway, as its absence would represent a 50% lower productivity and a cost increase of 95%. Producing the final product as a powder represents a 1.20% greater cost. Not only does the production under more favourable climatic conditions (southern Spain) removes the need for artificial lights and greenhouses, but it also would imply greater productivity (39.02 t/ha/year) and a reduced cost (23.08 €/kg DW of disrupted and dry biomass) at a scale of 100 ha. The main factor affecting CAPEX is the PBR, which range from 49.48 to 96.37% of the MEC. As for OPEX, the most critical elements vary with the projection: labour, energy, utilities, and other costs. The competitiveness of microalgae for aquaculture depends on a combination of different factors. Reducing the cost of the PBR and greenhouse, increasing the PE and widening the temperature range of the culture could reduce the cost by a further 76%

Milking exopolysaccharides from Botryococcus braunii CCALA778 by membrane filtration

The aim of this work was to optimize the efficiency of extraction and recovery, also known as ‘milking’ of exopolysaccharides (excreted polysaccharides, EPS) from continuous cultures of Botryococcus braunii CCALA778. First, an indoor process was developed and optimised, ensuring the highest milking efficiency without compromising culture viability. For this, photobioreactors were operated in a photo-chemostat mode under simulated outdoor conditions of a typical summer at AlgaePARC (51°59′44.1”N 5°39′26.2″E) in Wageningen, The Netherlands. Once a steady state was reached, areal productivities of 23 g m−2 d−1 and 3 g m−2 d−1 for biomass and EPS were achieved. EPS milking was done by membrane filtration of one reactor volume at the beginning of the dark period. After optimization, the maximum recovery of EPS, without damaging the cells, was 12%; yielding a daily EPS extraction rate of 0.36 g m−2 d−1. The optimised process was scaled-up and applied outdoors during the summer (at AlgaePARC facilities). Outdoor cultures showed 25% lower biomass productivity (17 g m−2 d−1) but an 25% higher EPS productivity (4 g m−2 d−1). The efficiency in the milking, however, decreased as compared to indoor results. Only 3% of the total content of EPS produced outdoors was milked (0.12 g m−2 d−1). To improve the EPS milking process, future research should focus on increasing the EPS extraction yield without negatively influencing its production by Botryococcus braunii.</p

Outdoor performance of Chlorococcum littorale at different locations

Our goal in the present study was to evaluate the potential for lipid production of two cell populations of the marine microalgae Chlorococcum littorale under different climate conditions. We selected, in a previous study and via fluorescence activated cell sorting (FACS), a new cell population of Chlorococcum littorale, namely S5. S5 showed a stable doubled triacylglycerol (TAG) productivity in comparison with the original population. A previously developed model was expanded to include day:night cycles and validated to predict biomass and outdoor TAG productivities at different locations. Four different locations were chosen to simulate the response of C. littorale to different day lengths and light intensities (the Netherlands, Norway, Brazil and Spain). Indoor experiments (simulated summer) were carried out with Original and S5, showing that S5 had a doubled TAG productivity under N-starvation. Finally, simulations of biomass and TAG productivities of Original and S5 at different locations were performed. At locations with lower light intensities, Norway and the Netherland s, biomass productivities were higher than at locations with higher light intensities, Brazil/Spain. Such results might be associated with light-saturation effects. TAG productivities, however, showed no effect of local light intensity. Locations at higher latitudes, Norway/Netherlands, cannot sustain phototrophic year-round production, hence, the yearly average TAG productivities were doubled in Brazil/Spain (from 1.4–1.6 to 3.0–3.2 g m − 2 d − 1 ). Likewise, C. littorale S5 was simulated with doubled TAG productivities when compared with Original, at all locations (2.5–2.7 (low light) to 4.7–5.2 g m − 2 d − 1 (high light)). The present results confirm the industrial potential of Chlorococcum littorale, both Original and S5, as a source of TAG. Furthermore, our results can be used for comparison and to estimate future production scenarios

Botryococcus braunii strains compared for biomass productivity, hydrocarbon and carbohydrate content

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