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
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.
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
C as CO ,
Food and Feed
Requirements for growing microalgae (autotrophic)
N, P, K, Ca, Fe,
Mg, Cl, S, etc.
C as CO2,
HCO3- & CO3
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
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
Standardization Difficult PossibleWeather dependence High Less because
protectedMaintenance Easy DifficultConstruction costs Low HighBiomass concentrations at harvesting
Overheating problems Low HighSuper dissolved oxygen concentrations
*Very high in thin-layer sloping systems
O2 + N
Biodiesel Protein Residue Other valuable products
Since there is no MANUAL or BLUE PRINT available to aspirant
commercial algal biotechnologists, the following are the realities of
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
excellence, but with
(with apology to the
Musina Spirulina as food supplement
Some ProjectsCO2 sequistration by Xtrata
Nannochloropsis for aquaculture
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.
with the Limpopo
River forming the
1) Annual average temperature higher than 18 oC (maximum
temperatures May-Aug = 24 oC, Dec-Feb = 37 oC ).
2) Minimal precipitation (
Depth 100 150 mm
Paddle Wheel mixed
2 x 2 m2
2 x 20 m2
2 x 500 m2
4 x 2000 m2
Musina Spirulina ProcessRaw waterStorage
8 Fin HDPE Paddle Wheel
Sweco Vibrating Sieve Construction
Rotor after a drying cycle of 6 hRotor after a drying cycle of 6 h
Warm turbulent atmosphere
For flash evaporation drying
Benefits brought to the community with this project were:
Job creation Training Science awareness Economic empowerment
Bioremediation of point source CO2emissionsBioremediation of point source CO2emissions
Ozone SO2 NOx
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
Global warming and climate change are
ascribed to increased atmospheric CO2concentrations
Green technologies are a requirement in the
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
The Carbon Neutral Process
The area needed and technology required would bevery costly to fix the CO2 produced from a mediumsized coal-fired electric power station.
Any photosynthetically driven CO2 fixation system wouldbe cyclic in the sense of diurnal and seasonal light/darkcycles.
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.
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
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
Further processes include:
Biological and chemical P removal
High Rate Algal Ponds (HARPs)
Advanced Pond Systems (APS)
HRAP William Oswald
Simple to operate
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
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
The third generation biofuels made from algae i