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-Universitδt 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 July 24, 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 July 24, 2014).

Share This




More Matter & Energy News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) — 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com
Boeing Ups Outlook on 52% Profit Jump

Boeing Ups Outlook on 52% Profit Jump

Reuters - Business Video Online (July 23, 2014) — Commercial aircraft deliveries rose seven percent at Boeing, prompting the aerospace company to boost full-year profit guidance- though quarterly revenues missed analyst estimates. Bobbi Rebell reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Car Market on the Rebound?

Europe's Car Market on the Rebound?

Reuters - Business Video Online (July 23, 2014) — Daimler kicks off a round of second-quarter earnings results from Europe's top carmakers with a healthy set of numbers - prompting hopes that stronger sales in Europe will counter weakness in emerging markets. Hayley Platt reports. Video provided by Reuters
Powered by NewsLook.com
9/11 Commission Members Warn of Terror "fatigue" Among American Public

9/11 Commission Members Warn of Terror "fatigue" Among American Public

Reuters - US Online Video (July 22, 2014) — Ten years after releasing its initial report, members of the 9/11 Commission warn of the "waning sense of urgency" in combating terrorists attacks. Mana Rabiee reports. Video provided by Reuters
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:
from the past week

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