1. Correspondence to: Rene H. Wijffels, Wageningen University, Bioprocess Engineering, PO Box 8129, 6700 EV Wageningen, the Netherlands.
E-mail: rene.wijffels@wur.nl
© 2010 Society of Chemical Industry and John Wiley & Sons, Ltd
Review
287
Microalgae for the production
of bulk chemicals and biofuels
Rene H Wijffels, Bioprocess Engineering, Wageningen University, the Netherlands
Maria J Barbosa, Food and Biobased Research, Wageningen University and Research Center, the Netherlands
Michel H M Eppink, Bioprocess Engineering, Wageningen University, the Netherlands
Received January 19, 2010; revised March 17, 2010; accepted March 18, 2010
Published online in Wiley InterScience (www.interscience.wiley.com); DOI: 10.1002/bbb/215;
Biofuels, Bioprod. Bioref. 4:287–295 (2010)
Abstract: The feasibility of microalgae production for biodiesel was discussed. Although algae are not yet produced
at large scale for bulk applications, there are opportunities to develop this process in a sustainable way. It remains
unlikely, however, that the process will be developed for biodiesel as the only end product from microalgae. In order
to develop a more sustainable and economically feasible process, all biomass components (e.g. proteins, lipids, car-
bohydrates) should be used and therefore biorefining of microalgae is very important for the selective separation and
use of the functional biomass components. If biorefining of microalgae is applied, lipids should be fractionated into
lipids for biodiesel, lipids as a feedstock for the chemical industry and w-3 fatty acids, proteins and carbohydrates
for food, feed and bulk chemicals, and the oxygen produced should be recovered also. If, in addition, production of
algae is done on residual nutrient feedstocks and CO2, and production of microalgae is done on a large scale against
low production costs, production of bulk chemicals and fuels from microalgae will become economically feasible.
In order to obtain that, a number of bottlenecks need to be removed and a multidisciplinary approach in which sys-
tems biology, metabolic modeling, strain development, photobioreactor design and operation, scale-up, biorefining,
integrated production chain, and the whole system design (including logistics) should be addressed. © 2010 Society
of Chemical Industry and John Wiley & Sons, Ltd
Keywords: microalgae; bulk chemicals; biorefinery process design
Introduction
M
icroalgae are receiving a lot of attention presently
because of their potential use as a feedstock for
the production of biodiesel. Worldwide research
programs are initiated to develop technology for the produc-
tion of biodiesel from microalgae and many new companies
have been developed and most probably will develop in the
future.
Microalgae have potentially an areal productivity superior
to traditional agricultural crops.1,2
Realistic estimates for
areal productivity are in the order of magnitude of 40-80
tonnes of dry matter per year depending on the technol-
ogy used and the location of production.3
In many cases,
estimates published are too high and sometimes higher than
theoretically possible. These overestimations lead to unre-
alistic expectations; even in the European Union Research
and Development framework, consortia are invited to submit

2. 288 © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd | Biofuels, Bioprod. Bioref. 4:287–295 (2010); DOI: 10.1002/bbb
RH Wijffels, MJ Barbosa, MHM Eppink Review: Microalgae for bulk chemicals and biofuels
proposals to develop demonstration projects with the objec-
tive of establishing a 10 ha production facility with productiv-
ity between 90 and 120 tonnes of dry algal biomass per year.
The objective is to build three of these demonstration plants
(www.cordis.europa.eu: FP7-ENERGY-2010-2 BIOFUEL
FROM ALGAE).
In contrast to terrestrial crops, hardly any production
capacity for microalgae exists at this stage. Production is
done in niche markets for high-value products, such as the
most common products carotenoids and w-3-fatty acids.
The world production of microalgae is about 5 million kg of
dry biomass with a total market volume of €1.25 billion. The
market price of microalgae is on average €250/kg dry bio-
mass.4
Nevertheless, microalgae are considered a very prom-
ising crop for production of biofuels due to their high areal
productivity in comparison to terrestrial crops and the lack
of competition for land that is suitable for agriculture –
microalgae can be grown on seawater. To make microalgae
really interesting as a source of biofuels, the cost price for
production needs to be reduced and the scale of production
needs to be increased significantly. We believe that techni-
cally this will be feasible, but it will take a tremendous effort
to realize this and we expect that development to a com-
mercial process will at least take 10 years.5
Simultaneously
with the development of the technology, it is important to
pay attention to the design of the whole system taking into
account the logistics of water, nutrient, and CO2 supply and
a complete life cycle analysis to determine at which scale and
locations production needs to take place.
For production of algal biomass for biodiesel purposes, it
is essential that the production capacity (hectares of culture)
increases and the cost of production decreases dramatically.
Presently there is no significant algal production capacity;
the technology is immature and needs to be fully developed,
implying that a large effort in research, pilot studies, and
demonstration studies is required. It is unrealistic to expect
that the technology of algal production will be competitive
for the energy market within the coming five years but with
sufficient effort it might become attractive after ten.
Microalgae contain 30–60% lipids that can be converted
into biodiesel.6
The value for diesel is presently €0.50/liter.
This indicates that the production cost of microalgae may
not be higher than €0.40/kg, excluding costs of extraction
and conversion of lipids into biodiesel. If, however, the
technology develops, the production capacity will gradually
increase and the production cost will reduce. As capacity
increases and the prices go down, new markets will open
and markets will evolve from niche products toward food,
feed, pharma, bulk chemicals, and finally also fuels.
In this review, we will describe the present status of the
technology and discuss the potential cost price of produc-
tion as well as the need for biorefining for development
of sustainable markets. Finally, we will describe the ideal
agenda for research and development of algal technology.
The present hype around microalgae is not realistic, but if we
have the patience and the resources to develop fundamen-
tal and applied research, the technology will develop as an
important pillar of sustainable production of large quantities
of biomass for food, feed, bulk chemicals, and energy.
Biodiesel from microalgae
Microalgae accumulate large quantities of hydrophobic com-
pounds. The best example of that is Botryococcus braunii.
Botryococcus braunii does not produce lipids, but less oxygen-
ated isoprenoids; almost alkane-like structures with approxi-
mately 32 to 38 C-atoms. These components can be used
in existing oil refineries. The concentration of these com-
pounds can be as high as 70% of the biomass. In addition,
the cell wall of Botryococcus is thin and the oil can be easily
extracted. The cells almost spontaneously excrete these oils
(Fig. 1). Unfortunately, Botryococcus is difficult to culture and
Figure 1. Botryococcus braunii excretes oil spontaneously.

3. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd | Biofuels, Bioprod. Bioref. 4:287–295 (2010); DOI: 10.1002/bbb 289
Review: Microalgae for bulk chemicals and biofuels RH Wijffels, MJ Barbosa, MHM Eppink
therefore isn’t so much used in development of processes for
production of biodiesel from microalgae. This example, how-
ever, shows that oil excretion could simplify part of the biore-
finery approach for other algae strains with oil excretion.
The production of lipids from microalgae, preferably
tri-acylglycerides, is receiving the most attention. The con-
centration varies between 20 and 60%. Accumulation to
high concentrations in lipid globules generally takes place
after stress.7
First algae are grown and then they need to be
stressed – for example by nutrient limitation – to induce
accumulation of lipids. Generally the biomass productivity
decreases substantially under these stress conditions.
At present, hardly any algae are produced for the produc-
tion of lipids for biofuels. Estimates are therefore very rough.
We estimate that with algae it will be possible to produce 20
000–80 000 liters of lipids per hectare per year. On the basis
of the present technology, the productivity will not be higher
than 20 000 liters per hectare per year; if the technology
develops, we might eventually reach 80 000 liters per year.
This is considerably higher than production via terrestrial
crops: palm and rapeseed oils are produced at 6000 and 1500
liters per hectare per year, respectively.
Lipids need to be extracted from the microalgae to produce
biodiesel. There are two processes to convert the lipids into
biodiesel: esterification and hydrogenation. In the case of
esterification, the glycerol esters are converted into methyl
esters.1
By catalytic hydro conversion, triglycerides are con-
verted into linear hydrocarbon chains. In hydrogenation, the
lipids are converted into alkanes.8
Feasibility study
Although large-scale processes for biodiesel production
from algae have not been developed, expectations of algae
for this application are very high. Production of algae needs
to take place on a large scale and against minimal costs.
Currently, algal products are on the market for equivalent
biomass values two orders of magnitude higher than they
may be for biodiesel production. The question is whether
algal biomass can be produced at a cost below €0.50/kg.
For this reason, we executed a feasibility study. In this
feasibility study, process designs were made for production
of algae in systems that could be built with the present
technology, without further technological advances. Three
systems were designed: an open pond raceway system, a
tubular photobioreactor and a flat panel reactor. Designs
were made at a scale of 1 hectare and at 100 hectares to
understand the effect of scale. The objective was not only to
calculate the absolute cost of production of 1 kg of algae, but
also to understand the cost factors involved in order to be
able to optimize the process.
The designs were based on industrial processes; costs
for tubing, maintenance, and operation were taken into
account. In the designs, we made conservative estimates: for
example, we used solar conditions in the Netherlands with
a moderate climate; if plastic materials were used for the
photobioreactor, it was assumed that the plastic needed to be
renewed every year; we assumed productivities that are cur-
rently obtained at large scale with these techniques; and we
assumed we had to buy CO2 and nutrients.
As an example, the production cost is shown in a flat
panel reactor system at a scale of 1 ha. The cost of produc-
tion is approximately €9/kg. The main cost factors in this
case are power and labor (Fig. 2). If the system is scaled up,
labor costs can be reduced significantly. The cost price for
biomass in a reactor of 100 ha is about €4/kg. A cost price
of €4/kg would be acceptable for the production of biomass
for high-value compounds but unacceptable for the produc-
tion of biodiesel. More than 24% of the cost was for energy
consumption; i.e. pumping around of water and sparging of
air/CO2 in the system. As a matter of fact, the energy input
was larger than the energy chemically stored in the biomass,
which makes the technology unsuitable for production of
biodiesel. We have to realize, however, that there has never
been a driver for those commercial companies currently
operating in the field of microalgae to reduce the cost of
energy. The cost of energy in this example is less than €2/kg
biomass. The total value of algal biomass for high-value
products is about €100/kg, which means there is hardly any
driver for the industry to reduce energy input.
In order to evaluate whether cost prices could be signifi-
cantly reduced if the technology is further developed for
biodiesel production, we performed a sensitivity analysis
and studied the effect of reducing specific cost factors; for
example, the source of CO2 and nutrients. In our cost cal-
culations, we assumed that these feeds had to be bought
and we then looked at the effect of getting these resources

4. 290 © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd | Biofuels, Bioprod. Bioref. 4:287–295 (2010); DOI: 10.1002/bbb
RH Wijffels, MJ Barbosa, MHM Eppink Review: Microalgae for bulk chemicals and biofuels
for free if they were obtained from residues. Another factor
we analyzed was a reduction of energy input to 10% of the
original value. We also assumed we could raise the produc-
tivity by assuming a photosynthetic efficiency of 7% instead
of the 5% we originally used. Finally we assumed that the
process would be applied in an area with more sunshine: the
island of Bonaire in the Caribbean. If all these factors were
included, a cost price for biomass production of €0.40/kg
could be obtained.
The cost prices of the other processes (raceway pond and
flat panel reactor) were in the same order of magnitude.
There was, however, a difference in the cost reduction that
could be obtained. While in the tubular photobioreactor, we
could reduce the cost price by 90% after optimization, we
could only reduce the costs in a raceway pond by 50%. The
reason for this is that raceway ponds are used much more
at larger scale and there is less room for improvement in
these systems. Although generally assumed that production
in photobioreactors is much more expensive than in a race-
way system, we found that after optimization, cost prices in
closed systems were actually lower than in a raceway pond.
Biorefining of microalgae
The next question is whether it is economically feasible to
produce biodiesel from microalgae if we are able to reduce
cost price of biomass production to €0.40/kg. If we assume
that algae contain 40% lipids and the value of biodiesel is
€0.50/liter, the value of the biomass used for biodiesel produc-
tion is only €0.20/kg. It also needs to be considered that costs
for extracting the lipid and converting the lipids into biodie-
sel were not taken into account. This means that it will not be
feasible to produce algae solely for the production of biodiesel.
For this reason we looked at the possibility of refining algal
biomass into different products and analyzed the total value
of the biomass. We did not assume a combination of high-
value products in niche markets because the market volumes
of high-value products and biodiesel are incompatible. We
assumed biorefining of algal biomass into products for bulk
markets making use of the functionality of the products. The
case is randomly chosen and is only used to analyze whether
1 ha
100 ha
potential
Iron frame Centrifuge westfalia separator AG
Centrifuge Feed Pump Medium Filter Unit
Medium Feed pump Medium preparation tank
Harvest broth storage tank Seawater pump station
Automatic Weighing Station with Silos Air Blowers
Installations costs Instrumentation and control
Piping Buildings
Polyethylene Culture medium
Carbon dioxide Media Filters
Air filters Power
Labor Payroll charges
Maintenance General plant overheads
7.9 /kg biomass
4.0 /kg biomass
0.4 /kg biomass
15 /GJ
Figure 2. Costs and cost factors for the design of flat panel photobioreactors at a scale of 1 and 100 ha.
Figure 3. Value of algal biomass per 1000 kg after biorefining.

5. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd | Biofuels, Bioprod. Bioref. 4:287–295 (2010); DOI: 10.1002/bbb 291
Review: Microalgae for bulk chemicals and biofuels RH Wijffels, MJ Barbosa, MHM Eppink
the total value of the biomass produced is sufficient to allow
production costs of €0.40/kg (Fig. 3).
We assumed production of algal biomass consisting of
40% lipids, 50% proteins and 10% carbohydrates. A more
detailed overview is presented in Carioca et al.6
If the lipid
fraction is not only used for production of biodiesel but also
as a feedstock for the chemical industry (e.g. in coatings) or
for edible oils (e.g. w-3-fatty acids) the lipid fraction of the
algae increases in value. We assumed in this case that 25% of
the lipids is used for these functional products with an esti-
mated value of €2/kg and 75% is used for biodiesel produc-
tion with a value of €0.50/kg.
In addition, proteins could be fractionated into a water
soluble fraction (e.g. Rubisco) of 20% and a water insoluble
fraction of 80%, taking into account that the water soluble
fraction has a food value (€5/kg) and the insoluble fraction a
feed value (€0.75/kg).
Finally a carbohydrate fraction of 10% was assumed. The
carbohydrates in algae are very low in cellulose. They are,
in general, storage products such as fructans, glucans, and
glycerol which can be used as chemical building blocks or
for production of bioenergy. We assumed the value of carbo-
hydrates to be €1/kg.
Besides these main products, there are additional byprod-
ucts, such as reduction of nutrients in waste streams and
production of oxygen. In waste-water treatment, the removal
of nitrogen compounds via nitrification and denitrifica-
tion is an expensive process; the cost of nitrogen removal
is €2/kg. Microalgae contain 70 kg of nitrogen per 1000 kg
of microalgae. If algal production would be combined with
waste-water treatment we would save €140 for nitrification
and denitrification per ton of algae produced. A similar
analysis could be made for phosphate.
Algae produce oxygen-rich gas. Per ton of algae 1600 kg of
oxygen-rich gas is produced. In aquaculture, oxygen-rich gas
is used for supply of sufficient oxygen to the fish. The value of
the gas produced is approximately €0.16/kg of oxygen. If the
total value of all these products is added up, we come to a total
value of the biomass of €1.65/kg of algae. Of course the refin-
ing of these components will be at a certain cost. The analysis
shows, however, that if algal biorefining is used, the total value
is higher (€1.65/kg) than the total cost for algae production
(€0.40/kg) and makes it worthwhile to develop this approach.
Overall, we can conclude that the production of only biodie-
sel from microalgae is economically not feasible but that an
integrated biorefinery concept of microalgae with biodiesel as
one of the products can lead to a feasible process.
Development of a new technology
We have shown that the production of microalgae for copro-
duction of biodiesel and bulk chemicals can become eco-
nomically feasible. In addition, if the technology develops,
we expect that the cost price of production of microalgae
will reduce gradually. Microalgae are now produced for
high-value products in niche markets; however, if the cost
price of production goes down; it is expected that new mar-
kets will open with every step in reduction. Initially, most
probably the production of edible oils for food and fish feed
will become feasible, but after some time production of bulk
chemicals, biomaterials, and biodiesel may also become fea-
sible. For that the technology needs to develop from a small-
sized activity to an industrial scale technology. We expect
that such a development will at least take ten years. For that
a multidisciplinary approach needs to be developed as sche-
matically shown in Fig. 4.
Systems biology
Systems biology in microalgae has hardly been developed.
In the first place, algae originate from different families,
Figure 4. Multidisciplinary approach for development of industrial
algae production.

6. 292 © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd | Biofuels, Bioprod. Bioref. 4:287–295 (2010); DOI: 10.1002/bbb
RH Wijffels, MJ Barbosa, MHM Eppink Review: Microalgae for bulk chemicals and biofuels
varying from prokaryotes like cyanobacteria to eukaryotes
like green algae (chlorophytes).
Establishing industrial production with algae requires
among others, in-depth knowledge of basic biological
functions and tools for steering the metabolism, with the
objective of improving, for example, the photosynthetic
efficiency in photobioreactors or enhancing lipid produc-
tivity. This can be done by an optimal design of condi-
tions inside the reactor or by metabolic engineering. A key
technology in the successful application of both optimal
conditions design and metabolic engineering is the avail-
ability of well-annotated genomes and quantitative tools for
genome-scale metabolic models that permit understand-
ing and manipulation of the genome. There are still very
few algae for which full or near-full genome sequences
have been obtained and transvection systems have barely
been developed. An additional challenge remains to inte-
grate the genome datasets with datasets from other levels
of biological organization. An integrated approach using
state-of-the-art technologies, such as genome sequencing,
transcriptomics, metabolomics, proteomics, metabolic
modeling (fluxomics), and bioinformatics, is needed in
order to gain the best possible insight into metabolic path-
ways leading to the product of interest. This systems biol-
ogy approach is the basis for the enhancement of the physi-
ological properties of algae strains and the optimization
of algae production systems. Even though this approach is
used more and more in microbial and plant sciences, it is
still new in algal biology. It is expected that research in this
field will develop quickly and tools will become available to
improve photosynthesis in algae, to enhance productivity
of lipids in microalgae, and many other features that may
lead to a reduction in cost prices or a higher reliability of
the whole process chain.
Metabolic flux modeling
Genome-based metabolic flux models are in their infancy
and are expected to be developed in the coming years. With
these metabolic flux models, we will be able to understand
and steer metabolism in microalgae with the objective of
improving, for example, the photosynthetic efficiency in
photobioreactors or enhancing lipid productivity. Metabolic
flux models can be used both to design the conditions in a
reactor such that a better process is obtained and to target
metabolic engineering approaches.
Strain development
Only a few microalgal strains are produced commercially
(e.g. Spirulina, Chlorella, Dunaliella, Haematococcsu and
Nannochloropsis). These strains are probably not the best
strains for the production of biodiesel. For this reason we
need to screen for new strains or modify the strains such
that optimal production of lipids for biodiesel becomes feasi-
ble. Ideally microalgae should have the following qualities:
• High productivity (of metabolites)
The productivity of biomass should be high. If it is pos-
sible to produce large quantities of biomass per surface
area, the cost of production reduces significantly. In
addition to productivity of biomass, the productivity
of metabolites, such as lipids, should also be high. Very
often the process is done in two stages. Biomass is grown
and then stressed at which stage the lipids start to accu-
mulate. Although the concentration of lipids obtained is
high, the volumetric productivity is in general low. It is
important to select or improve strains in such a way that
a high productivity in lipids is obtained.
• High yield on light
Related to productivity is the yield on light. The maxi-
mum yield on solar light is 9%. In practice, it is a lot
lower. Strains have already been developed with smaller
antenna sizes allowing a higher photosynthetic yield at
high light intensities.
• Robust
The process, and consequently the microalgae, needs
to be robust. For biodiesel production, the scale of pro-
duction needs to be so large that axenic operation or
advanced process control will hardly be possible. The
strains therefore need to be stable under production cir-
cumstances and stronger than possible infections. Ideally
it should be possible to grow the algae on a large scale
under extreme conditions such as high or low pH, high
temperatures, or high salinity.
• Grow at high pH
While the supply of CO2 is essential for growth of algae
at high productivities, it is also an important cost factor.
Ideally CO2 should be used from the atmosphere, but the

7. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd | Biofuels, Bioprod. Bioref. 4:287–295 (2010); DOI: 10.1002/bbb 293
Review: Microalgae for bulk chemicals and biofuels RH Wijffels, MJ Barbosa, MHM Eppink
concentration is too low to make high productivities pos-
sible. Alternatively, the CO2 source is a residual gas that
needs to be bubbled through the water column. As gas
bubbling already requires energy, it is important that the
mass transfer of CO2 is efficient. At high pH (10–11), the
mass transfer is much higher and in addition the opera-
tional conditions are selective.
• Insensitive for oxygen
Microalgae produce oxygen. In many processes, oxygen
accumulates to high concentrations. At high concentra-
tions of oxygen, the productivity of microalgae reduces
considerably. Nevertheless, we would prefer to operate
processes at high oxygen concentrations because degas-
sing of the system requires energy and oxygen-rich gas is
a nice byproduct.
• Flocculate
Harvesting microalgae is expensive. Microalgae are
small and mostly individual cells. For that reason
centrifugation is mostly used as a harvesting method.
The biomass concentration is in general also low.
Centrifugation of diluted streams requires a large-capac-
ity centrifuge and consequently harvesting is expensive.
If algae flocculate, harvesting costs could be reduced sig-
nificantly and filtration, sedimentation or flotation can
be used for harvesting instead of centrifugation. Ideally
algae would flocculate spontaneously at a certain stage of
the process.
• Large cells with a thin cell wall
Microalgae are, in general, relatively small and have
a thick cell wall. In order to break cells to extract the
products, very harsh conditions need to be used (e.g.
mechanical, chemical, physical stress). This makes break-
ing up cells not only very expensive but also affects the
functionality of compounds like proteins. Ideally the
extraction could be so mild that water extraction at low
temperatures can be applied. This requires cells that are
easy to break but are strong enough that no shear dam-
age takes place during production. Small spherical cells
with a thick cell wall, like Nannochloropsis, clearly are
not the ideal algae for this reason.
Photobioreactor design and operation
The ideal photobioreactor requires low investment costs and
low operational costs but still has a high productivity and is
scalable. Design of photobioreactors is not easy as a large sur-
face-to-volume ratio is required for efficient supply of solar
light. At the same time, the high surface-to-volume ratio
makes scale-up difficult in respect to mass and heat transfer.
On top of that, solar conditions change continuously. Many
types of photobioreactors have been developed and probably
Figure 5. Thin plastic film photobioreactor of Proviron (A) and Solix Biofuels (B).
(A) (B)

8. 294 © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd | Biofuels, Bioprod. Bioref. 4:287–295 (2010); DOI: 10.1002/bbb
RH Wijffels, MJ Barbosa, MHM Eppink Review: Microalgae for bulk chemicals and biofuels
many more will still be developed. For evaluation of designs,
it is important to compare performance of the different
systems under the same operational conditions for longer
periods of time. In the feasibility analysis we showed that
photobioreactors could become competitive if investment
costs were reduced significantly. Investment costs should be
less than €15/m2
.9
Thin plastic film bioreactors are presently
developed for this reason. Examples are shown in Fig. 5.
Scale-up
Developments in the microalgae field are mainly driven
by end users. For the end users there is a limited supply
of biomass to develop further processes. For this reason
only, some production capacity needs to be realized.
Single products like biodiesel from algae can then be
developed and tested and the biorefinery program can be
developed.
In addition, there is no or hardly any experience with
production of algae on a larger scale under outdoor condi-
tions for longer periods of time. For this reason, it is very
important not only to do research at laboratory scale but
also to develop pilot programs to evaluate and compare their
performance as a basis for design of demonstration-scale
facilities.
In order to facilitate quick development of the technology
research at laboratory scale, pilot scale and demonstration
scale programs should run parallel with a good exchange of
information such that technology developed in the labora-
tory can be tested under realistic conditions and research at
laboratory scale can be done for the problems encountered at
large scale.
Biorefinery
Economical, feasible production of microalgae for biodiesel
will only be possible if it is combined with production of
bulk chemicals and food and feed ingredients. Research and
development of biorefineries is therefore very important in
this field to explore mild cell disruption, and extraction and
separation technologies on algal biomass. Compounds such
as w-3-fatty acids, carbohydrates, pigments, vitamins, and
proteins should maintain their functionality in this process
and at the same time scalability, low energy costs, and ease
of use also need to be taken into account.
Integrated process chain
So far, individual productions steps have been discussed and
it is highly recommended to develop an integrated algae pro-
duction chain by combining the different process units into
a complete process. Uncertainties in specific process units
(upstream) may have an impact on the process units down-
stream in the production chain. Therefore, whole production
processes, upstream and downstream, should be developed
and tested on pilot and demonstration scales.
Systems design
Production of microalgae on a large scale will be complex
with respect to logistics and space needed. Productivity of
microalgae does not only depend on the availability of sun-
light, but on the availability of land, water resources, CO2,
and nutrients as well. Transport of the different feedstocks
over long distances most probably is not a feasible option.
This makes it more difficult to determine beforehand what
the best locations for production are and what the scale of
production should be. At this moment it is unclear if future
algae production plants will be of enormous scale or whether
it will become an activity similar to farming land crops
nowadays.
To design the system processes, logistics and Life Cycle
Assessments needs to be analyzed.
Conclusions
We have discussed production of microalgae for biodiesel.
We have shown that although algae are not yet produced on
a large scale for bulk applications, there are opportunities
to develop these processes in a sustainable way. However, it
is unlikely that the process will be developed for biodiesel
as the sole end product. In order to develop a sustainable
and economically feasible process, all biomass components
should be used; therefore biorefining of microalgae is very
important for the development of the technology.
The production technology of microalgae is, however,
immature and efforts have to be made to develop an eco-
nomical sector. In respect to the development of the technol-
ogy, it is proposed to develop multidisciplinary research on
systems biology, metabolic flux modeling, strain develop-
ment, photobioreactor design, scale-up, biorefining, inte-
grated process chain, and systems design.

9. © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd | Biofuels, Bioprod. Bioref. 4:287–295 (2010); DOI: 10.1002/bbb 295
Review: Microalgae for bulk chemicals and biofuels RH Wijffels, MJ Barbosa, MHM Eppink
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Dr René H. Wijffels
Dr René H. Wijffels is a professor at Wage-
ningen University. He heads the Bioprocess
Engineering Group which is researching the
development of new biotechnological proc-
esses for manufacturing of pharmaceuticals,
healthy food ingredients, bulk chemicals, and
biofuels. Dr Wijffels received his MSc in Envi-
ronmental Technology and his PhD in Bioprocess Engineering.
Dr Maria Barbosa
Dr Maria Barbosa is a researcher at the busi-
ness unit Biobased Products at Wageningen
University and Research Centre. Her present
area of expertise is the cultivation and biorefin-
ing of microalgae, with a focus on applied re-
search. Dr Barbosa holds a PhD in Bioprocess
Engineering obtained at Wageningen University.
Dr Michel Eppink
Dr Michel Eppink is Associate Professor at the
Bioprocess Engineering Group at Wageningen
University. He is also Department Head of
Downstream Processing at the Biopharma-
ceutical Division of Synthon BV. Dr Eppink re-
ceived his MSc in Biology/Chemistry in 1993
from the University of Utrecht and his PhD in
1999 from the Agriculture University of Wageningen.
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Posten C, et al., Second generation biofuels: High-efficiency microalgae
for biodiesel production. Bioenerg Res 1(1):20–43 (2008).