This is a podcast of Scripps Institution of Oceanography at UC San Diego.
To learn more about how you can support Scripps, visit us online
at scripps.ucsd.edu. Around the world,
people are looking for new solutions to mitigate the harmful buildup of
greenhouse gases
such as carbon dioxide and counter the dangers posed by the planet's warming
climate.
Foremost in this quest, is the search for new ways to loosen humanities
dependence on fossil fuel consumption.
Recently, renewed hope has been placed on deriving
fuel from biologically based sources, such as plants.
Yet the once promising prospects have generating expansive amounts of fuel
from land-based plants such as corn and soybean,
had declined in recent years. Now
researchers at Scripps Institution of Oceanography, UC San Diego's division of
biological sciences
and around the San Diego region are looking to the
oceans for a next-generation biofuel source.
I'm a marine biologist and in the ocean
the ecosystem's supported by the photosynthesis of the microscopic
plants.
So my interests are to study and model mass and energy flow in ocean ecosystems and it all
starts with absorption of light from the Sun
by the microscopic plants, the phytoplankton. Phytoplankton are
extremely efficient, for example
they represent less than one percent of the biomass of plants on earth,
yet they produce about half of the oxygen
of all plant photosynthesis on Earth. But from a sustainability point of view,
they're also extremely compelling. For example,
the organisms we study in the sea, grow in seawater
its salt water. Salt water is not good for human drinking
or for our cows to drink or for irrigation water.
However, we can grow the algae in seawater
and we can put the growth systems on non-airable land
that can't otherwise be used for agriculture so we can have a huge impact
on producing biofuel in feed protein
on non-airable land, using seawater therefore saving
our precious top soils and saving our precious water,
which is going to be a crisis. Furthermore, algae can take CO2 up
or it requires you to directly from the water medium they grow in. Therefore
it's possible to put CO2
from a point source, like a power plant stack gas,
put it straight into the sea water and then deliver it
to the algae system, very inexpensively via
pipeline and this way the algae will be taking up the co2
to create their biomass. Despite the enticing prospects of algae,
much remains to be learned about how they grow and produce the oils
called lipids, that scientists and engineers can turn into biofuel.
Bill Gerwick, who explores marine sources to develop biomedical products
to treat human diseases,
recently began researching lipid oils in algae.
So when micro algae, when we
take a a little annoculum, a few cells and put it into a flask,
they're surrounded by nutrients and
light that we provide and so they grow and they divide and mainly what
they're producing are the cell walls and the proteins, and the DNA
that allow them, that are necessary for growth and for
new cellular composition. As those cultures mature though
and nutrients start to diminish and
have used that supply of nitrogen and phosphorous
up, out of there culture supply, they
continue to photosynthesize but they have no place to put that photosynthate
and what they do then is they put it into lipid reserves,
not unlike the way that we store away when we have a
a turkey dinner and store away some as a
oils around our midsection. Algae store away the extra photosynthate
as lipid oils and this is a source of energy for them
in times when maybe there's not enough sunlight. So
these are the very same oils that we want to harvest
biofuels and ultimately use in a capacity like a
biodiesel. So we've been engaged in some preliminary
work in this area and
I'm actually very excited about some of the things that were finding and that
is that
we have been able to grow cultures in the laboratory of some of the same micro
algae that are being
considered as candidates for large pond cultures out in the
perhaps out in the Imperial Valley or elsewhere
in desert type locations and
we've been able to add small molecules to these cultures which
greatly expand their growth rate and their production of oils.
Scripps research biologist Mark Hildebrand has been investigating the
genetics
underlying lipid production in algae.
Marine algae produce lipid oils when they are starved for nutrients.
When adequately fed, they produce carbohydrates instead.
Hildebrand is looking into tiny algae called diatoms
to find out how the organisms dictate or partition
lipids or carbohydrates. The results could deliver vital new information for
biofuel development.
So the idea is that if we can understand the underlined gene
regulation, that will help us understand how the pathway that partitions carbon
into carbohydrates or into lipids
is regulated and that'll be the first step
and so subsequent to that, once we identify those genes
the other thing we're doing in our lab is developing genetic manipulation
approaches so we can
introduce DNA into diatoms and change their
metabolic pathways
with some more developing. The idea is if we identify a gene that's critical for
this partitioning for example, and we find that well, if we knock that gene out
or if we overexpressed that gene, we might be able to
permanently make the cells accumulate lipid rather than just do it under
nutrient limitation conditions.
So that's kind of the ultimate goal for what we're trying to do.
Beyond the research frontiers, the researchers acknowledge
that a range of challenges remains in order to turn the bio-fuel promise of
algae
into the clean efficient energy solution needed for the environmental health of
the planet.
Currently the the most economically viable way of doing this is to grow
algal cultures in large outdoor ponds and
they're open systems and so contamination with other organisms is a
really big issue.
And one of the goals would be to develop
or isolate strains that could grow, say at extreme conditions or extreme salinity
or extreme pH so
that other competing organisms wouldn't grow well.
So you would then take the lessons you've learned from your model system
find a strain or species that grows well under the extreme conditions
and try to adapt that into those. There are many challenges
to go from this lab based studies that I do
that can predict outcomes to actually making
commercially viable products. I think these are not so much scientific
problems specifically, where we don't know the answer
We know what we have to do. It has to do with interdisciplinary engineering solutions.
The biologist, the chemist, the physicist, the engineers, the economist,
all have to work together in an integrated way, interdisciplinary way
to find the integrated solutions across the full value chain.
This has been a presentation of Scripps
Institution of Oceanography at UC San Diego.