This course was produced by the Algae Technology Educational Consortium and UC San Diego with funding from the Algae Foundation, the National Renewable Energy Lab, and the U.S. Department of Energy. Algae are an extremely diverse group of organisms that can be found in almost every ecosystem on the planet, and they play an essential role for life on earth. They are little bio-factories that use the process of photosynthesis to create chemical compounds that we can utilize for food, feed, medicine, and even energy. We’ve brought together some of foremost algae experts from industry and academia to teach you the fundamentals of algae. This course will cover what algae are, why they are important, and why we are interested in them for both their environmental benefit, as well as their use for products. You will also explore the vast diversity of algae including the characteristics and applications of some of the main types of algae that are in commercial use today. Later you will learn about algal ecology and how interactions with environment, including pests and predators, affect algal productivity. And finally you will examine the processes of algae bio-manufacturing including production processes, as well as some of the products, benefits, and challenges that impact our ability to make commercially viable products from algae.
Post-Harvest Processing
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Introduction to Algae
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Algae Biomanufacturing Part 2
In this section we will examine the important steps of algae biomanufacturing. This includes techniques for productive culture growth, harvest, and creating useful products from biomass.
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Dr. Stephen MayfieldProfessor of Molecular Biology
University of California San Diego
Ira "Ike" LevineProfessor, Natural and Applied Sciences
University of Southern Maine
Hi, my name is Michael Burkhart.
I'm a Professor of Chemistry at Biochemistry at the University of California, San Diego.
And I'm the Associate Director of the California Center for Algae Biotechnology.
And I'm here to talk to you about algae post-harvest processing.
So as you will have learned from some of the other talks that you've heard,
we produce algae through a process of cultivation,
and then we need to take that algae,
remove the water from it,
and extract the hydrocarbons from it,
and that's what I'm going to be talking to you today in the extraction process.
Now, the whole purpose why we're doing that is so that we can
take those products and modify them
into useful products for us in our daily lives.
And so there will be other talks that you're going to hear
about turning these molecules that we extract from
algae into useful products like polymers and biofuels, things like that.
So what you're going to hear from my discussion today is first,
you're going to know where algae oil is found in the cell.
You're going to learn how vegetable oil is purified,
and how we took that information and translated it into,
come up with a way to purify algae oil.
And then you're going to learn about some of the next steps in using that algae oil.
So just for the basics and again,
these are some things that you're going to hear about later.
But polyurethanes are a really interesting target for us these days,
where we're learning to take renewable oils that come out of algae,
and turn them into polymers like polyurethanes.
And what's kind of amazing is how polyurethanes can be
found in all kinds of products that are around you,
from seat cushions to the soles of shoes,
to insulation in housing,
to things like plastic chairs.
And here is just a depiction of some of
the chemistry that we do beginning with the triacylglyceride algae oil,
and going through a polymerization event.
And basically a polyurethane is an addition of
a monomer which is shown with
the blue dot with another monomer that's shown as the green dot,
and that forms a polymeric matrix.
And so what we do with our algae oil is we convert it
into what that green dot represents in order for us to make the biofuels.
And again, you'll be learning more about that later.
One quick comment is that when you're
trying to work with any system in particular with algae,
you can't start and demonstrate something on
a very small scale and expect it to translate perfectly into the very large scale.
And so as we start developing technologies for algae to apply them to useful products,
we often need to go through a whole series of
improvements and modifications as we start scaling these bigger and bigger.
And that's really what I'm going to be talking to you today about the extraction process.
So we begin by looking at how edible oils are extracted and
purified in order to sell them
in the grocery store and for you to use them in your kitchen.
And it's actually a very complex process that begins with a dried grain typically,
like corn or canola,
and that then gets extracted and purified through
a number of different processes before it actually gets put into the bottle,
and sold to the grocery store.
So in looking at that,
we're forced with a bit of a dilemma because the algae that we are
growing is coming out of a liquid culture.
And so it has a lot of water around it,
and even when you extract it,
you dewater it and take 90 to 95 percent of the water away,
you're still left with a wet biomass,
and it's very energy intensive to try to dry that.
And so one of the questions that we had,
is that number one,
if we take that algae biomass that has water in it,
is there any way that we can do these extractions in the wet biomass?
We also need to realize that there are different types of algae,
and algae store their energy in different compartments.
And I'm going to show that in a minute,
where the different lipids are found in the algae cell.
And so we needed to think about all these different issues about removing the water,
and about the location of the fatty acids for us to then
think about how we are going to apply this challenge to algae.
And one of the things we realized we needed to first do is to come up with a way to
extract all of the lipids and oils from the algae while it is still wet,
while it still has water around.
And one of the biggest problems with that is that the methodology for
large scale really didn't exist back when we
were talking about doing this type of research.
And so kind of to show you some of those challenges,
here we're now looking at the top right at a picture of algae,
and it turns out that the lipids are actually scattered all around the algae.
So not only can it be found in lipid bodies,
which is the kind of the yellow portion inside that cell,
where the triacylglycerides or oils are stored,
but then those lipids are also found in the membranes around the outside of the cell,
and also the membranes inside the chloroplast.
And so we really wanted a methodology where we could extract all of those lipids at once.
So there's a number of different ways of doing that.
And typically organic solvents are necessary to extract those lipids out,
but keep in mind many of these lipids,
particularly the ones that are in the lipid membrane are actually highly charged,
and so we have to think about being able to remove
those phospholipids with an organic solvent that
could tolerate both the hydrophobic portion
of that plus the portion of it that was very charged.
And so looking at a lot of the different literature,
there turned out to already be one method that was
used and continues to be used which is called The Bligh and Dyer method.
And the problem with Bligh and Dyer is that it uses as an organic solvent,
this chlorinated solvent called chloroform,
and chloroform is extremely expensive.
It's also toxic and it's really not appropriate for a large scale methodology.
And so we needed to come up with a new methodology,
and what you see on the right as a two-pot methodology.
And we rationalize that what we could do is add a mixture of
organic solvents to our wet biomass of algae.
We could heat it up.
And what you see on top of the flask on the left is a condenser,
whereas that organic solvent begins to evaporate,
it can condense back down into the pot.
And then as those lipids are being removed from the algae biomass,
they will flow over into that pot on the right, where they would be stored.
And also on the right,
that would also be heated up so that both systems would be in a reflux,
and we would have a continuous movement of those lipids from the left pot to the right.
And so what you can see here is just this cycle that you begin at
the top with your algae biomass very green and in the bottom.
And then as you as you conduct this experiment over the course of about four hours,
pretty much all of the lipids and also many of the pigments which are
coloured green are going to move from the left flask into the right one.
So we did this with algae and also a number of other different organisms,
and so what you see here is just a demonstration of that.
Where the dark gray bars are the Bligh and Dyer method,
and the light gray bars is the Two-pot method.
And we basically found that we could do this not only at a fairly small one point five
liter level but we could also scale it up all the way to
11 liters in a very efficient manner.
And so we realized that this two pot method really
could be used for a number of different types of algae,
and that's very important because we're looking at many different strains in our centre,
and that we can really extract almost
all of the lipids that are present in that cellular mass.
This is just a demonstration of the lipids that we were able to get out of this system.
What you see on the right hand portion of this slide
or what's known as thin layer chromatography or TLC.
Where you spot your extracted material at the bottom.
You just put a little spot of it on a plate that has silica on it,
and then you move solvent up that plate and
it separates out all of the different components,
and each spot on there is a different molecule.
So we can actually scrape off some of that silica,
and we can put it onto a more quantitative analytical measurement,
which is the graph on the left that's called a
GCMS or a Gas chromatography-mass spectrometer.
And we can identify what each spot represents,
each of the molecular species,
and so we can go in and determine exactly what we've extracted,
and where it's found in the cell.
So, once we've done that,
we've done all of the extraction that we need.
And now the next question is how are we going to take
those products of the extraction of algae,
and convert them into useful products?
And that's what you're going to hear as you move forward in this sequence.
So thanks very much for listening.
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