Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Get to Work, Enzymes!

08.04.2013
High yield: Cell-free enzyme cascade makes hydrogen from xylose

Fuel cells are a highly promising means of producing electricity. However, the hydrogen they require is still largely obtained from coal, oil, or natural gas. Producing hydrogen from less expensive biomass is an attractive alternative, but has not produced sufficient yields to date.

In the journal Angewandte Chemie, a team of American and Mexican researchers has now introduced a cell-free biosystem of thirteen enzymes that can produce hydrogen from xylose, one of the main components of plants, in yields of over 95 %.

Xylose is a pentose (a sugar molecule containing five carbon atoms), and is one of the main building blocks of lignocellulosic biomass—wood and parts of woody plants. It is not economically feasible to separate xylose from the other components of biomass for the production of hydrogen. There are microorganisms that can convert xylose and glucose, the building block that makes up cellulose, into hydrogen. However, the yields are very low.

Y.-H. Percival Zhang at Virginia Tech (Blacksburg, USA) and his co-workers in the USA and Mexico have thus resorted to a trick: They are using the enzymes used by the microorganisms, but in a cell-free system. They combined thirteen enzymes and various cofactors like NADPH into a complex cascade that do not exist in the natural metabolic systems. In a bioreactor, they were able to produce hydrogen from xylose with a yield of over 95 %.

The downside: In the first step of the reaction, xylose is isomerized into xylulose, which must be activated in a second step by addition of a phosphate group. This requires ATP (adenosine triphosphate), the "energy carrier" of cells, to "pump" chemical energy into the enzyme cascade. Unfortunately, ATP is a very expensive material. The thing that depends on ATP is the splitting of the energy-rich bonds between individual phosphate groups. The researchers thus had an idea: They wanted to replace the ATP with a more economical substance, polyphosphate, which also contains energetic phosphate bonds. However, this requires a xylulokinase, an enzyme that attaches phosphate groups to xylulose, and can use polyphosphate instead of ATP.

Polyphosphate is found in volcanic rocks and in deep-oceanic steam vents. Primeval organisms may have used this substance. The researchers isolated the gene for a xylulokinase from thermotoga maritima, a thermophilic microorganism found in such environments, and used genetic engineering to produce the enzyme. As they hoped, this enzyme can also use polyphosphate and can successfully replace the ATP-dependent xylulokinase in the enzyme cascade.

This team had previously developed a synthetic enzymatic route for the production of hydrogen from cellulose. Now both of the major components of biomass, cellulose and xylose, can be converted together in a new approach for the more economical production of hydrogen.

About the Author
Dr Percival Zhang is an Associate Professor of Biological Systems Engineering Department in the College of Agriculture and Life Sciences and the College of Engineering at Virginia Tech and has been working in the biofuels area for over 15 years. One of his goals are to replace crude oil with renewable sugars. He is the recipient of the Biotechnology and Bioengineering Daniel IC Wang Award and DuPont Young Faculty Award.

Author: Y.-H. Percival Zhang, Virginia Tech, Blacksburg (USA), http://filebox.vt.edu/users/ypzhang/zhang.htm

Title: High-Yield Production of Dihydrogen from Xylose by Using a Synthetic Enzyme Cascade in a Cell-Free System

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201300766

Y.-H. Percival Zhang | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Designer cells: artificial enzyme can activate a gene switch
22.05.2018 | Universität Basel

nachricht Flow of cerebrospinal fluid regulates neural stem cell division
22.05.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Designer cells: artificial enzyme can activate a gene switch

22.05.2018 | Life Sciences

PR of MCC: Carbon removal from atmosphere unavoidable for 1.5 degree target

22.05.2018 | Earth Sciences

Achema 2018: New camera system monitors distillation and helps save energy

22.05.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>