Micro Algal Biotechnology
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Transcript of Micro Algal Biotechnology
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Microalgal Biotechnology: Opportunities and Challenges for
Bioremediation, Bioenergy, Food and Feed Production
Johan U GrobbelaarDepartment of Plant SciencesUniversity of the Free StateBloemfontein, South Africa
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The intensive growth and production of microalgae inphotobioreactors and the marketing of biomass, productsor benefits for economic gain.
My Definition of Microalgal Biotechnology:
This answers amongst othersthe South African Governmentand the Department of Scienceand Technology calls to placeSouth Africa amongst the worldleaders in the application ofbiotechnology and economicempowerment.
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Microalgae as model organisms for BIOTECHNOLOGY
Why do microalgae have a competitive advantage over conventional higher plants?
They have very high growth rates Due to their high surface to volume ratio they have e.g.
high uptake rates The are cosmopolitan and strains can tolerate The are cosmopolitan and strains can tolerate
extremes They do not require good agriculture soils or water They can be grown in dense photobioreactors They produce high valued products They require 1/20 the water compared to conventional
agriculture to produce the equivalent useablebiomass, or 30 times more oil per area than rapeseed
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C as CO ,
Biomass
Phytonutrients
Bioenergy
Wastewater
Food and Feed
Bioremediation
Requirements for growing microalgae (autotrophic)
Microalga
N, P, K, Ca, Fe,
Mg, Cl, S, etc.
C as CO2,
HCO3- & CO3
=, pH
Turbulence
Optimal
Temperature
Photobioreactor
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BIOREACTOR = container in which living organisms carry out biological reactions
Applied phycologists have made a distinction between open
and closed photobioreactors (PBR)
Closed Tubular PBR Open Cascade PBRClosed Tubular PBR Open Cascade PBR
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Parameter Open ponds (raceway ponds)
Closed systems (PBR systems)
Contamination risk High LowWater losses High LowCO2-losses High Almost noneReproducibility of production
Variable but consistent over time
Possible within certain tolerances
Process control Complicated Less complicatedStandardization Difficult Possible
Major Differences
Standardization Difficult PossibleWeather dependence High Less because
protectedMaintenance Easy DifficultConstruction costs Low HighBiomass concentrations at harvesting
Low* High
Overheating problems Low HighSuper dissolved oxygen concentrations
Low High
*Very high in thin-layer sloping systems
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Green Technology
O2 + N
Recycledwater
CO2
Ethanol/Methanol/Butanol
Biodiesel Protein Residue Other valuable products
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Since there is no MANUAL or BLUE PRINT available to aspirant
commercial algal biotechnologists, the following are the realities of
the day:
In most cases interested parties re-invent the wheel
Advice is at most sought from one expert with some input
from engineering and technological services
Engineering excellence often over shadows biology
Not so Simple
An example of
engineering
excellence, but with
predictable poor
photobiology.
(with apology to the
producer)
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Musina Spirulina as food supplement
Some ProjectsCO2 sequistration by Xtrata
Nannochloropsis for aquaculture
and bioenergy
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1st Step was to decide on an organism and to produce a prospective investors document.2nd Step was to identify suitable areas for producing Spirulina, taking only two criteria into consideration, i.e. annual temperature cycle and the availability of water.
Musina Spirulina
Northern Cape
with the
Orange River
Limpopo Province
with the Limpopo
River forming the
border with
Zimbabwe and
Botswana
LED funding
determined
Musina
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1) Annual average temperature higher than 18 oC (maximum
temperatures May-Aug = 24 oC, Dec-Feb = 37 oC ).
2) Minimal precipitation (
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Open Raceways:
Depth 100 150 mm
HDPE Lined
Paddle Wheel mixed
CO2 supply
Musina system:
Production Ponds:
2 x 2 m2
2 x 20 m2
2 x 500 m2
4 x 2000 m2
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Musina Spirulina ProcessRaw waterStorage
Nutrient Solution
Production Ponds
Harvesting
Drying
CO2
Quality Control
Packaging &
Marketing
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8 Fin HDPE Paddle Wheel
Contruction
Sweco Vibrating Sieve Construction
Contruction
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Grgens Turbo-Rotor
Mill/Dryer
Heater
Turbo-Rotor
Mill/Dryer
Bag Filter
Rotor after a drying cycle of 6 hRotor after a drying cycle of 6 h
Warm turbulent atmosphere
For flash evaporation drying
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Benefits brought to the community with this project were:
Job creation Training Science awareness Economic empowerment
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Greenhouse Gasses:
CO2 Ozone
Bioremediation of point source CO2emissionsBioremediation of point source CO2emissions
Ozone SO2 NOx
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The Problem
Atmospheric CO2 levels have increased from
260 to >360 ppm during the last century
The increase is directly correlated with
industrialization and green house gas
emissionsemissions
Global warming and climate change are
ascribed to increased atmospheric CO2concentrations
Green technologies are a requirement in the
global economy
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Many options have been proposed and
employed to sequistrate CO2, especially from
point source emissions. Common to all are
their limited capacity. Options available are:
Chemical binding with e.g. Mg(OH)2, NaOH, or Ca(OH)2, Methane synthesis, Methane synthesis, Deposition in earth gas fields or in the deep oceans, and Biological processes including photosynthetic fixation or
specific enzymatic reactions.
Green Plants have been fixing CO2 for at least 3 billion years
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The Carbon Neutral Process
Algal Biomass
Coal
Neutral CO2Cycle
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The Reality:
The area needed and technology required would bevery costly to fix the CO2 produced from a mediumsized coal-fired electric power station.
And,
Any photosynthetically driven CO2 fixation system wouldbe cyclic in the sense of diurnal and seasonal light/darkcycles.
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However,No higher plant phytomass production system cancompete with microalgae in terms of production rates andpotential adaptation to different climatic and growthconditions.Although the CO2-uptake will be cyclic, either diurnaland/or seasonal (light dependant), it is possible to combineand/or seasonal (light dependant), it is possible to combineit with other CO2-fixing processes.The phytomass fixation should form part of a holistic CO2reduction programme.The produced phytomass would have an economic value(e.g. as bioenergy, food or feed, fine chemicals,biofertilizer, etc.), including environmental taxes, againstwhich the costs could be deferred. Most other processesessentially imply no return and represent a net loss.
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We are of the opinion that algal biotechnology hold the most promise as a real means of bioremediation for CO2 point source pollution and sustainability of the planet.
We are of the opinion that algal biotechnology hold the most promise as a real means of bioremediation for CO2 point source pollution and sustainability of the planet.of the planet.of the planet.
Workshop recently held at the Science Museum, London
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Wastewater Treatment
World-wide wastewater is treated using
a variety of processes, referred too as
Sustainable nutrient management.
Anaerobic digestion is widely used where digestion strips
nitrogen and phosphorus from the wastewater, in what is
known as a activated sludge process. During digestion,known as a activated sludge process. During digestion,
organic matter is converted to carbon dioxide, methane,
trace gases, water, and a stabilized slurry. A major problem is
the resultant digester effluent and stabilized manure slurry.
The latter requires further treatment.
Common in South Africa
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Further processes include:
Algae
Involved
Biological and chemical P removal
Wetlands (man-made)
High Rate Algal Ponds (HARPs)
Advanced Pond Systems (APS)
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Bacteria
ProtozoaAlgae
Nutrients
CO2
O2
Wastewater
HRAP William Oswald
ALBAZOD
ProductTreated
Wastewater
Benefits:
Cheap
Simple to operate
Odorless
Valuable products
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Use Integrated ecological engineering principals
Minimal odour Simple operation and maintenance
Advantages of the HRAP and ASP
Simple operation and maintenance Construction and operating costs typically
50% that of mechanical treatment plants Significant energy and nutrient recovery
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Biofuels and Bioenergy All petrol sold on the UK must contain 5 % biofuel. By 2020 of all transport fuels sold in the EU must contain
10 % biofuel. The Energy Independence and Security Act of the US
determines that by 2022, 36 billion gallons of biofuelmust be produced.
Do biofuels increase food scarcity and price?scarcity and price?Yes, if conventional crops are used making algal bio-fuels even more attractiveAlgae do not compete
with conventional agriculture or food
production
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The third generation biofuels made from algae is not only a carbon neutral solution, it:
It has 1.5 times more energy per litre fuel compared to Jet-A1-Fuel
Up to 40 % less NOxs 60 times less SOxs
Is this a dream?
No
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Biofuels a reality in aviation
Propelled exclusively by algal produced biofuelalgal produced biofuel
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Amazing claims are made, many of them in popular media, i.e.YouTube, Google, Yahoo and many other, such as thepotential production of >1 200 L oil ha-1 d-1! This equates to abiomass productivity of about 400 g(dw) m-2 d-1!.
V
o
l
u
m
e
t
r
i
c
P
r
o
d
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c
t
i
v
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(
g
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)
2
3
4
5
xy 84.33119.0 +=
Data from Lee (2001)
d
-
1
) 140
160
Optical depth (cm)0 5 10 15 20
V
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r
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c
P
r
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(
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1x
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Optical depth (cm)0 5 10 15 20
A
r
e
a
l
P
r
o
d
u
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t
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v
i
t
y
(
g
(
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)
m
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d
0
20
40
60
80
100
120
Highest productivities reported for PBRs () and open ponds () according to Lee (2001)
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The upper limit of photosynthesis at 8 % photosynthetic efficiency would yield about 200 g (dw) m-2 d-1efficiency would yield about 200 g (dw) m-2 d-1
or 14 tons of biomass per week per ha, or 700 tons per ha per year
At present we are only at about 25 30 g (dw) m-2 d-1and at a photosynthetic efficiency of around 1 %
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Conclusions
Present microalgal production rates can be doubledwith a systematic analysis of a number of factors.This would require collaboration and R&D fundingwithout restrictive conditions
Algal bioprospecting is at its infancy and new specieswith unique properties are found almost daily,especially in extreme locationswith unique properties are found almost daily,especially in extreme locations
Microalgal biotechnology offers unique opportunitiesfor economic empowerment and upliftment,especially in rural and agricultural marginal areas
South and southern Africa has ideal locations formega microalgal biotechnology projects
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Open Raceway Ponds will be the reactor of choice for any mega microalgal production plants at least in the foreseeable future.
Raceway ponds suffer from amongst others, the formation of dead zones, laminar flow and consequently poor nutrient and metabolite exchange rates, large optical depth and limited fluctuating light regimes.light regimes.
Vertical mixing is imperative to ensure high productivities.
A systematic analysis of improving mixing in raceway production ponds is needed and CFM should be used to model and optimise designs.