Researchers engineer breakthrough for biofuel production

Nov 21, 2013 by Mario Aguilera
Scripps oceanography researchers engineer breakthrough for biofuel production
A scanning electron microscope image of the diatom Thalassiosira pseudonana.

(Phys.org) —Researchers at Scripps Institution of Oceanography at UC San Diego have developed a method for greatly enhancing biofuel production in tiny marine algae.

As reported in this week's online edition of the Proceedings of the National Academy of Sciences, Scripps graduate student Emily Trentacoste led the development of a method to genetically engineer a key growth component in .

In the quest to loosen humanity's dependence on traditional fossil fuel consumption, and with it rising concentrations of carbon dioxide and their damaging impacts on the environment, finding economically viable fuels from biological sources has been elusive.

A significant roadblock in algal research surrounds the production of lipid oils, the fat molecules that store energy that can be produced for fuel. A catch-22 has stymied economically efficient biofuel production because algae mainly produce the desired lipid oils when they are starved for nutrients. Yet if they are limited in nutrients, they don't grow well. With a robust diet algae grow well, but they produce carbohydrates instead of the desired lipids for fuel.

In a significant leap forward that clears the lipid production hurdle, Trentacoste and her colleagues used a data set of genetic expression (called "transcriptomics" in laboratories) to target a specific enzyme inside a group of microscopic algae known as diatoms (Thalassiosira pseudonana). By metabolically engineering a "knock-down" of fat-reducing enzymes called lipases, the researchers were able to increase lipids without compromising growth. The genetically altered strains they developed, the researchers say, could be produced broadly in other species.

"These results demonstrate that targeted metabolic manipulations can be used to increase accumulation of fuel-relevant molecules.… with no negative effects on growth," said Trentacoste. "We have shown that engineering this pathway is a unique and practical approach for increasing lipid yields."

"Scientifically this is a huge achievement," said Mark Hildebrand, a marine biology professor at Scripps and a coauthor of the study. "Five years ago people said you would never be able to get more lipids without affecting growth negatively. This paper shows that there isn't an intrinsic barrier and gives us hope of more new things that we can try—it opens the door to a lot more work to be done."

In addition to lowering the cost of biofuel production by increasing lipid content, the new method has led to advances in the speed of algal biofuel crop production due to the efficient screening process used in the new study.

"Maintaining high growth rates and high biomass accumulation is imperative for algal biofuel production on large economic scales," the authors note in the paper.

"It seems especially fitting that Scripps-UC San Diego is displaying so much leadership in the field of sustainable biofuels from algae, for instance with the California Center for Algae Biotechnology starting here, given the history of the institution playing such a pivotal role in climate change research," said paper coauthor William Gerwick, a distinguished professor of oceanography and pharmaceutical sciences
at Scripps's Center for Marine Biotechnology and Biomedicine
and UC San Diego's Skaggs School of Pharmacy and Pharmaceutical Sciences. "But these advances do not happen in isolation, and the current project is a great illustration of how different labs can collaborate to achieve greater advances than possible singly."

Explore further: Study finds algal cells create fat more quickly than thought, could aid biofuel research

More information: Metabolic engineering of lipid catabolism increases microalgal lipid accumulation without compromising growth, Published online before print November 18, 2013, DOI: 10.1073/pnas.1309299110

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User comments : 10

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henk_nijsingh
not rated yet Nov 21, 2013
Do I understand well, that you don't need much nutrients to get biofuel with this process? That would indeed be a big breakthrough.
PPihkala
not rated yet Nov 21, 2013
henk:
"A significant roadblock in algal biofuel research surrounds the production of lipid oils, the fat molecules that store energy that can be produced for fuel. A catch-22 has stymied economically efficient biofuel production because algae mainly produce the desired lipid oils when they are starved for nutrients. Yet if they are limited in nutrients, they don't grow well. With a robust diet algae grow well, but they produce carbohydrates instead of the desired lipids for fuel."

Now these modified versions grow happily with unlimited nutrients and at the same time they produce lipids.
henk_nijsingh
not rated yet Nov 21, 2013
PPihkala:
So still nutrients are needed. Phosphor however is pretty scarce and should be used for food production. So this is a problem, unless you can recycle the phosphor when producing biofuel.
gjbloom
5 / 5 (1) Nov 21, 2013
The show-stopping challenge facing algal biofuel is still the extraction of the oil from the algae. Until someone persuades the algae to excrete oil droplets that can be skimmed from the top of the pond, algal biofuel will remain tantalizingly out of reach.

Also, algal biofuel requires a source of concentrated CO2, so it can only extend an existing carbon fuel burning industrial process, not supplant it.
NikFromNYC
1 / 5 (10) Nov 21, 2013
Invasive species are one thing but these things might as well be real alien invaders. How would you even test their safety minus another Earth to test it out on? There is no healthy counterpoint activism towards green *energy* Frankensteins, no more than there is towards bat and hawk chopping Gaian crucifixes. I imagine a fully green Earth soon, no humans, no trees, no insects, just green goo! Instead, activists are chaining themselves to low overall emissions nuclear and fracking sites, all to effectively turn vital warming into overly rapid and thus potentially biohazardous warming and kill poor people by doubling good and energy prices,
NikFromNYC
1 / 5 (9) Nov 21, 2013
Typo: good > food

Typo: , > .

betterexists
1 / 5 (5) Nov 21, 2013
Metabolically Engineering the knocking down of Lipases that break down lipids helps in saving the lipids produced for later derivation of Biofuels.

So, the more the Nutrients...The greater the growth of diatom and larger the lipid production.

But it is also said more work is needed though!

PPihkala:
So still nutrients are needed. Phosphor however is pretty scarce and should be used for food production. So this is a problem, unless you can recycle the phosphor when producing biofuel.

betterexists
1 / 5 (5) Nov 21, 2013
Oceans have all the nutrients on this earth...Diatoms in the Oceans get what all they Need.
And Diatoms are Plentiful.

PPihkala:
So still nutrients are needed. Phosphor however is pretty scarce and should be used for food production. So this is a problem, unless you can recycle the phosphor when producing biofuel.

henk_nijsingh
not rated yet Nov 22, 2013
Oceans have all the nutrients on this earth...Diatoms in the Oceans get what all they Need.
And Diatoms are Plentiful.


And recylcle the Phosphor as well! So you have two products from this algae.
ForFreeMinds
1 / 5 (5) Nov 25, 2013
... these things might as well be real alien invaders. How would you even test their safety minus another Earth to test it out on? ... I imagine a fully green Earth soon, no humans, no trees, no insects, just green goo! Instead, activists are chaining themselves to low overall emissions nuclear and fracking sites, all to effectively turn vital warming into overly rapid and thus potentially biohazardous warming and kill poor people by doubling good and energy prices,


It seems you a knack for science fiction. Has it not occurred to you that one can test this algae in water in a laboratory to see if/how it survives when exposed to competing algae and other bacteria/viruses/fungi? And one can test it for toxicity as well, since some algae is toxic such as dinoflagellates of the genus Alexandrium and Karenia, or diatoms of the genus Pseudo-nitzschia. http://en.wikiped...al_bloom

In the meantime, why not go swimming in the naturally created red tide algae blooms?

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