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 ,

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

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

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

Green Technology

O2 + N

Recycledwater

CO2

Ethanol/Methanol/Butanol

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

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)

Musina Spirulina as food supplement

Some ProjectsCO2 sequistration by Xtrata

Nannochloropsis for aquaculture

and bioenergy

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

1) Annual average temperature higher than 18 oC (maximum

temperatures May-Aug = 24 oC, Dec-Feb = 37 oC ).

2) Minimal precipitation (

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

Musina Spirulina ProcessRaw waterStorage

Nutrient Solution

Production Ponds

Harvesting

Drying

CO2

Quality Control

Packaging &

Marketing

8 Fin HDPE Paddle Wheel

Contruction

Sweco Vibrating Sieve Construction

Contruction

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

Benefits brought to the community with this project were:

Job creation Training Science awareness Economic empowerment

Greenhouse Gasses:

CO2 Ozone

Bioremediation of point source CO2emissionsBioremediation of point source CO2emissions

Ozone SO2 NOx

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

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

Algal Biomass

Coal

Neutral CO2Cycle

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.

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

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

Further processes include:

Algae

Involved

Biological and chemical P removal

Wetlands (man-made)

High Rate Algal Ponds (HARPs)

Advanced Pond Systems (APS)

Bacteria

ProtozoaAlgae

Nutrients

CO2

O2

Wastewater

HRAP William Oswald

ALBAZOD

ProductTreated

Wastewater

Benefits:

Cheap

Simple to operate

Odorless

Valuable products

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

production

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

Biofuels a reality in aviation

Propelled exclusively by algal produced biofuelalgal produced biofuel

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!.

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Highest productivities reported for PBRs () and open ponds () according to Lee (2001)

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 %

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

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.