Scientists find a 'switch' to increase starch accumulation in algae

November 2, 2018, Tokyo Institute of Technology
Cultivation of the unicellular red alga C. merolae in the laboratory. Credit: Sousuke Imamura

Results from a collaborative study by Tokyo Institute of Technology and Tohoku University, Japan, raise prospects for large-scale production of algae-derived starch, a valuable bioresource for biofuels and other renewable materials. Such bio-based products have the potential to replace fossil fuels and contribute to the development of sustainable systems and societies.

A "switch" controlling the level of content in algae has been discovered by a research team led by Sousuke Imamura at the Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology (Tokyo Tech).

Reported in The Plant Journal, the study focused on the unicellular red alga Cyanidioschyzon merolae. The researchers demonstrated that starch content could be dramatically increased in C. merolae through inactivation of TOR (target of rapamycin), a protein kinase known to play an important role in cell growth.

They observed a notable increase in the level of starch 12 hours after inactivation of TOR through exposure to rapamycin, and this led to a remarkable ten-fold increase after 48 hours.

Importantly, the study details a mechanism underlying this profound increase in starch content. Using a method called liquid chromatography-tandem mass spectrometry (LC-MS/MS), the researchers examined subtle changes in the structure of more than 50 proteins that might be involved in "switching on" the process of starch accumulation. As a result, they pinpointed GLG1 as a key protein of interest. GLG1 acts in a similar way to glycogenin, an enzyme found in yeast and animal cells, which is known to be involved in the initiation of starch (or glycogen) synthesis.

Compared with the control, inactivation of TOR resulted in an approximately ten-fold increase in starch content in C. merolae after 48 hours. Credit: Sousuke Imamura

The mechanism will be of immense interest to a wide range of industries seeking to scale up and value-added biochemicals production.

For example, the findings could accelerate the production of environmentally friendly fuel additives, pharmaceuticals, cosmetics, and bioplastics that are now in high demand with the phasing out of and straws in many parts of the world.

Algae, compared with land plants, are very appealing due to their high photosynthetic productivity and relative ease of cultivation. Starch, triacylglycerols (TAGs) and other algal biomass constituents are increasingly viewed as a promising and powerful way to contribute to the Sustainable Development Goals (SDGs) outlined by the United Nations.

The phosphorylation status of GLG1, which is regulated by TOR signaling, determines the ON/OFF switch for starch accumulation in the cells. Starch is a good carbon resource for chemicals that are applied in a wide range of industries. ('P' denotes phosphorylation.) Credit: Sousuke Imamura

The research team notes that more studies using other algal species, as well as higher plants such as Arabidopsis thaliana, could yield further information about the fundamental molecular mechanisms behind starch accumulation. "This information will help to develop technologies to improve starch biosynthesis productivity and concomitantly improve sustainable biomass and bioenergy production," Imamura says.

Explore further: Scientists identify enzyme that could accelerate biofuel production

More information: Imran Pancha et al, Target of rapamycin (TOR) signaling modulates starch accumulation via glycogenin phosphorylation status in the unicellular red alga Cyanidioschyzon merolae, The Plant Journal (2018). DOI: 10.1111/tpj.14136

Related Stories

The plant that only grows when the going's good

July 2, 2014

Scientists have identified a new mutant plant that accumulates excessive amounts of starch, which could help to boost crop yields and increase the productivity of plants grown for biofuels.

Starch from yeast

November 23, 2016

Researchers at ETH Zurich have produced starch in yeast—the first time this has been achieved in a non-plant organism. The new model system now makes it easier for them to investigate how starch is formed and what role ...

Making oil from algae – towards more efficient biofuels

April 19, 2017

The mechanism behind oil synthesis within microalgae cells has been revealed by a Japanese research team. This discovery could contribute to the development of biofuels. The findings were published on April 4 in Scientific ...

Artificial control of starch synthesis in plants

March 17, 2015

A research group is the first in the world to identify the gene that controls starch synthesis in plants. Their study, entitled "CO2 Responsive CCT protein, CRCT Is a Positive Regulator of Starch Synthesis in Vegetative Organs ...

Recommended for you

Galactic center visualization delivers star power

March 21, 2019

Want to take a trip to the center of the Milky Way? Check out a new immersive, ultra-high-definition visualization. This 360-movie offers an unparalleled opportunity to look around the center of the galaxy, from the vantage ...

Physicists reveal why matter dominates universe

March 21, 2019

Physicists in the College of Arts and Sciences at Syracuse University have confirmed that matter and antimatter decay differently for elementary particles containing charmed quarks.


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Nov 02, 2018
Tyrrhenian Sea, Mediterranean Sea, Black Sea, Caspian Sea, Issyk Kul LaKe etc., can be used for them, since they are self-contained waters !
not rated yet Nov 02, 2018
Tyrrhenian Sea, Mediterranean Sea, Black Sea, Caspian Sea, Issyk Kul LaKe etc., can be used for them, since they are self-contained waters !
not rated yet Nov 02, 2018
oh, betterextinction. How will you convince, all those people already using those seas & lakes to give up their livelihoods for your claim to priority use?

I find it interesting the bodies of water you did NOT have on your list. Gotta wonder at your racist expectations & bloated ego of entitlement?

Such as the Lakes Geneva & Constance but then nobody messes with the Swiss.

Also the Great Lakes of North America. As recent events prove, those people are crazy! A sane man wouldn't want to piss them off.

Of course there is always the Baltic Sea... But then? You go interrupting their herring in sour cream supply? It's going to be a race to see which of the bordering countries winds up doing a redcap dance on your quivering body. Maybe they'll share?

Lake Baikal? Whoops, Mongols!

be, I'm sure. if you get right on it & if you search long enough? You'll eventually discover a puddle some place, where you can splash around in & brew up your starchy algae.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.