Featured Research

from universities, journals, and other organizations

What green algae are up to in the dark

Date:
February 14, 2013
Source:
Ruhr-University Bochum
Summary:
How do green algae produce hydrogen in the dark? Biologists have now uncovered a mechanism for the production of the gas which has hardly been examined before; usually, researchers are interested in light-driven hydrogen synthesis.

Hydrogen production in the dark: The unicellular green alga Chlamydomonas cannot only produce H2 using solar energy, but also in the dark. The RUB researchers uncovered the combination of the proteins responsible.
Credit: © AG Photobiotechnologie, RUB

How green algae produce hydrogen in the dark is reported by biologists at the Ruhr-Universität Bochum in the Journal of Biological Chemistry. Biologists have uncovered a mechanism for the production of the gas which has not been examined in depth before; as researchers are mostly interested in light-driven hydrogen synthesis.

"Hydrogen could help us out of the energy crisis," says Prof. Dr. Thomas Happe, head of the working group Photobiotechnology. "If you want to make green algae produce more hydrogen, it is important to understand all the production pathways."

Green algae produce hydrogen under stress -- even in the dark

Single-celled green algae of the type Chlamydomonas are microscopically small organisms: ten of them fit side by side on a human hair. In some ways, microalgae are not so very different from higher plants, such as trees. For example, they also perform photosynthesis. Unlike land plants, they can use light energy for the production of molecular hydrogen H2. "However, Chlamydomonas and co only form hydrogen under stress," says Thomas Happe. "The disposal of the energy-rich gas serves as a kind of overflow valve so that excess light energy does not damage the sensitive photosynthetic apparatus." Chlamydomonas can also produce hydrogen in the dark. Although this fact has been known for decades, H2 synthesis in the absence of light has barely been studied because much less of the gas is produced in the dark than in the light. Moreover, it is complicated to isolate large quantities of the key enzyme of the dark-reaction, the so-called pyruvate:ferredoxin oxidoreductase. The RUB researchers nevertheless tackled the project.

Hydrogen production in the dark mimicked in vitro

Happe's team reconstructed the core of the dark hydrogen production in vitro, thus demonstrating the underlying mechanism. In order to get to the proteins involved, the researchers had these produced by bacteria. First they introduced the corresponding genes of the green algae into the gut bacterium Escherichia coli, for example, the gene for the pyruvate:ferredoxin oxidoreductase. E. coli then produced the proteins according to this blueprint. Happe's team isolated them from the bacterial cells and examined them like a construction kit. In the test tube, the biologists analysed how different combinations of proteins interacted with each other under specific environmental conditions.

"Ancient enzyme" discovered

In so doing, they found out that, under stress in the dark, the algae switch to a metabolic pathway which is normally only found in bacteria or single-celled parasites. "Chlamydmonas has an evolutionarily ancient enzyme," explains Jens Noth from the working group Photobiotechnology. "With the help of vitamin B1 and iron atoms, it gains energy from the breakdown of sugars." This energy is then used by other green algal enzymes, the hydrogenases, to form hydrogen. The unicellular microalgae switch on this metabolic pathway when they suddenly encounter oxygen-free conditions in the dark. Because, like humans, the green algae need oxygen to breathe if they cannot draw their energy from sunlight. The formation of hydrogen in the dark helps the cells to survive these stress condition. "With this knowledge, we have now found another piece of the puzzle to get an accurate picture of H2 production in Chlamydomonas," says Thomas Happe. "In future, this could also help to increase the biotechnologically relevant light-dependent H2 formation rate."


Story Source:

The above story is based on materials provided by Ruhr-University Bochum. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. Noth, D. Krawietz, A. Hemschemeier, T. Happe. Pyruvate:Ferredoxin Oxidoreductase Is Coupled to Light-independent Hydrogen Production in Chlamydomonas reinhardtii. Journal of Biological Chemistry, 2012; 288 (6): 4368 DOI: 10.1074/jbc.M112.429985

Cite This Page:

Ruhr-University Bochum. "What green algae are up to in the dark." ScienceDaily. ScienceDaily, 14 February 2013. <www.sciencedaily.com/releases/2013/02/130214103820.htm>.
Ruhr-University Bochum. (2013, February 14). What green algae are up to in the dark. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2013/02/130214103820.htm
Ruhr-University Bochum. "What green algae are up to in the dark." ScienceDaily. www.sciencedaily.com/releases/2013/02/130214103820.htm (accessed October 22, 2014).

Share This



More Matter & Energy News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com
What Is Magic Leap, And Why Is It Worth $500M?

What Is Magic Leap, And Why Is It Worth $500M?

Newsy (Oct. 22, 2014) — Magic Leap isn't publicizing much more than a description of its product, but it’s been enough for Google and others to invest more than $500M. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins