Sustainable Pathways for Algal Bioenergy
Sustainable Pathways for Algal Bioenergy Sustainable Pathways for Algal Bioenergy
THE BIOREMEDIATION AND PHOTOPHYSIOLOGY EXPERIMENTS IN
PILOT PBRs WITH AIMS OF MECHNISITIC MODELS DEVELOPMENT
A Silkina, N Ginnever
Centre for Sustainable Aquatic Research,
Swansea University
Sustainable Pathways for Algal Bioenergy
The EnAlgae Project
WP1
Cultivation & processing
WP2
Routes to market
WP3
Guiding industry and policy
Data collection from 9 pilot facilities Best practice sharing Outreach
Economic Modelling Life Cycle Analysis Regulation and Policy
Smart information and data tools
Sustainable Pathways for Algal Bioenergy
Objectives of EnAlgae project
- Reduce risk and accelerate implementation of pilots;
- Implement algal biotechnologies within process chains;
- Generate reliable data to inform the development of an ICT (modelling) decision support tool
- Provide product and process descriptions
- Develop and share best practice among algal biomass and bioenergy producers across NWE
Sustainable Pathways for Algal Bioenergy Sustainable Pathways for Algal Bioenergy
EnAlgae Lead Partner – Centre for Sustainable Aquatic Research (CSAR)
Swansea University
• PBR capacity ~ 5000L • monitoring and (bio)chemical analysis …. • research for harvesting and processing • modelling tool developement
Sustainable Pathways for Algal Bioenergy
EnAlgae Targets for remediation
Test suitability of waste stream use : agricultural, fish farm and AD municipal waste as nutrients source
Compare the Nitrogen and Phosphorus uptake by different species in different cultivation PBR
Compare the productivity of species
Provide the data set for modelling tool
Sustainable Pathways for Algal Bioenergy
Bioremediation – Why use waste?
A number of cost/efficiency advantages
Environmental advantages
Phosphate sources are scarcer and will be economically unviable to mine by 2030
Waste nutrients source can help to reduce the mining of phosphorous and recycle this valuable mineral
Difficulties of preparation (e.g. filtration) associated with using liquid and solid waste sources
Liquid wastes- high in Ammonia -toxic to algae
Not have an optimal nutrient profile
Algae need adaptation to the waste source during initial cultivation
Sustainable Pathways for Algal Bioenergy
Species used
Chlorella minutissima
Scenedesmus sp.
Isolate from steel industrial site
Sustainable Pathways for Algal Bioenergy
Experimental conditions
15-25 days of cultivation in tubular PBR
Batch and Semi continuous mode
Close monitoring of biological parameters –
cells, biovolume, cellular C:N:P:Chl
Water chemistry and biochemistry analysis –
DIN, DIP, pH, T, PFD; lipid, carbohydrates
Log-in data-
pH, T; light
Sustainable Pathways for Algal Bioenergy
• Cultures were able to grow using waste nutrients • Cultures again entered a growth phase after partial harvest
growth rate
Results of growth
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Chlorella minutissima
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Scenedesmus sp.
Sustainable Pathways for Algal Bioenergy
Nutrient uptake by algae
• Waste nutrients are gradually taken up by the algae during cultivation
• P and N uptake
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Nutrient uptake during semi-continuous cultivation of Scenedesmus sp.
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Phosphate
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Nutrient uptake during semi-continuous cultivation of Chlorella minutissima
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Phosphate
Sustainable Pathways for Algal Bioenergy
PSII photoefficiency
Fv/Fm is the efficiency of photosystem 2 (PSII), the main light harvesting and processing complex in microalgae Can be used as a measure of cell stress
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Fv/Fm Chlorella minutissima
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Sustainable Pathways for Algal Bioenergy
Biochemical composition summary
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Diary waste remediation Scenedesmus sp.
% Carb composition
% Lipid composition
% Protein
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1 2 3 4 56
78
Diary waste remediation Chl. minutissima
Sustainable Pathways for Algal Bioenergy
Growth using fish waste
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Biovolume Chlorella minutissima
CONTROL
Trout waste
• The specific growth rate is similar to control sample
• Waste nutrients are gradually taken up by the algae during cultivation
• P is accumulated in cell
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Ammonia µmol/L
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Sustainable Pathways for Algal Bioenergy
Summary & Conclusion Species N uptake
rate
P uptake
rate
Max
Productivity
Producti
on rate
mg(N)L-1d-1 mg(P)L-1d-1 (g L-1) (g L-1 d-1)
C. minutissima
Control
5.27 ±0.8 0.41±0.1 1.73 ±0.08 0.12
C. minutissima
experimental
7.17 ±0.4 0.43±0.1 1.56 ±0.07 0.11
Scenedesmus sp.
Control
6.82 ±0.5 0.39±0.1 2.03 ±0.1 0.11
Scenedesmus sp.
Experimental
7.17 ±0.4 0.37±0.1 1.13 ±0.05 0.09
• Cultures were successfully grow using waste nutrients • Nutrient uptake related regulatory standards of waste release • Potential exploitation of algal biomass
Sustainable Pathways for Algal Bioenergy
Design of PBR comparison
Vertical and horizontal
Tubular reactors were compared
In control and waste remediation
condition, productivity is higher in vertical system with Ø 110 mm(Causerma et al, 2011)
The specific biomass (e.g. reach on lipids) quickly achieved on horizontal tubular PBRØ 43 mm
Sustainable Pathways for Algal Bioenergy Sustainable Pathways for Algal Bioenergy
Lighting and Harvesting: The
effect on the growth and
photophysiology of
Nannochloropsis oculata
Dr Naomi Ginnever, Dr Alla Silkina, Professor Kevin Flynn
Sustainable Pathways for Algal Bioenergy
Experiment and Rationale
In order to develop the photosynthetic and lighting portion of the Enalgae model experiments were undertaken to establish the effect of photoperiod (at a consistent photodose) and harvesting on the growth, photophysiology, physiology and biochemistry.
Experiments were undertaken in a 400L tubular bioreactor, which was artificially lit using metal halide lights. The photodose (15.471 mol photons m-2) was maintained over 4 experimental runs. 2 had a photoperiod of 11 hours and 2 had a photoperiod of 7 hours and 20 minutes. Supplied nutrient levels were calculated based on the known average cellular N content and the desired cell density
Sustainable Pathways for Algal Bioenergy
Methodology
Samples were taken daily for cell counts and PAM fluorescence analysis PAM fluorescence measurements were made using a Walz PhytoPAM and these data were analysed using an iterative curve fitting solution (Eilers and Peeters (1988) This provided several photosynthetic parameters which are useful indicators of cell health, stress and light acclimation The quantum efficiency of photosystem II (Fv/Fm) is a very valuable measure of the overall cell health/stress Light saturation coefficient (Ek) indicates the light acclimation state of the cells
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Initial Results
The cultures were not harvested until 40 million cells were reached A 25% harvest was performed 3 times reducing the cell numbers to 30 million cells
N=2, Experimental replicates
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Max div.day-1 =0.733, 0.711
Sustainable Pathways for Algal Bioenergy
Initial Results
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The Fv/Fm dropped dramatically after inoculation and after the initial partial harvest There then appeared to be an acclimation as the dramatic drop was not observed post partial harvest again
The carotenoid content in the cultures of both experimental photoperiods increased significantly during the run From 0.5 ng (106 cells) to 1.75 ng (106 cells) and 0.65 ng (106 cells) to 2.1 ng (106 cells) (both P= <0.05)
Sustainable Pathways for Algal Bioenergy
Initial Results
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The Ek increase increased post innoculation The Ek curve then saturated, and did not increase further This is likely due to the reduction in light per cell as the culture density increased meaning the cells do not need to become acclimated to a higher light level
The ratio of Chl a to carotenoids decreased during the growth curve in both cultures
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Discussion and Conclusions
The analysis of the biomass of is at an early stage and will be analysed in detail to fully understand the effect of different photoperiods and light levels on the photosystems and cellular composition Work is also being completed to investigate the effect of photoperiod using different LED colour mixes Data from outdoor experimental runs at different times of year are also being incorporated into the model to complete this component of the model
Sustainable Pathways for Algal Bioenergy
Discussion and Conclusions
The data suggests that despite the photodose being the same, the increased light level results in a longer lag phase After the 3rd harvest there is also a slower recovery Therefore it is recommended that a lower light level be used for longer photoperiod The higher light level did result in a non-significantly higher carotenoid content
Sustainable Pathways for Algal Bioenergy
Discussion and Conclusions
The initial partial harvesting had a negative effect on the photophysiology and resulted in a slight reduction in div.day However this effect was not observed after the second harvest At the 3rd harvest only the higher light level was negatively effected Therefore it is clear harvesting may have a negative effect if a large harvest is performed and at high light levels.
Sustainable Pathways for Algal Bioenergy
THANK YOU FOR YOUR ATTENTION
[email protected] [email protected]
Sustainable Pathways for Algal Bioenergy
The Enalgae model and decision support tool will be available for use by industry in NW Europe after the project is complete
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