FAU researchers find mechanism that makes root sweet

[caption id="attachment_148" align="alignleft" width="300"] The surface – the reflecting rectangle – has molecules applied to it. The FAU researchers examine these carrier surfaces, which are used in technologies such as organic solar cells, for their properties. (Image: Max Amende/FAU)[/caption] FAU researchers examine how molecules arrange themselves on surfaces used in new technologies It is a little like throwing pieces of a puzzle at a magnetic board and hoping they will fall into place by themselves. This is roughly what scientists do when they apply molecules to surfaces in order to create materials for new technologies such as organic solar cells. So far, they lack the knowledge to place the molecules on the surfaces in a controlled manner. A research group recently founded at FAU, funCOS, aims to provide that knowledge. The German Research Foundation (DFG) has now given the green light to the team of scientists led by Prof. Dr. Jörg Libuda, Chair of Chemistry and Pharmacy. Scientists have modelled organic solar cells or electronic components on nature where molecules have important functions: porphyrins, for instance, absorb the sunlight during photosynthesis in plants, converting the energy and passing it on. Porphyrins are now to do the same thing in organic solar cells. For power to be generated, however, the molecules need to be applied to carrier surfaces. The scientists place the molecules in a solvent, immerse the carrier in the solution – ‘and then you hope for as many molecules as possible to cling to the surface in an orderly manner,’ explains the speaker of funCOS, Prof. Jörg Libuda. So far, scientists still depend on serendipity: how many molecules are bound to the surface, what chemical bonds they form and which chemical reactions they trigger – the researchers can control none of these things so far. The order of the molecules is of vital importance if technologies such as our example of organic solar cells are to function: if they are placed on the surface in the wrong position or irregularly, malfunctions ensue. This is where the research group FOR 1878 ‘funCOS – Functional Molecular Structures on Complex Oxide Surfaces’ comes into play: 15 research groups at FAU are already examining the areas where molecules and carrier surfaces meet, which are known as molecule/oxide interfaces. ‘We want to gain control of the molecules in order to get access to certain functions, such as collecting sunlight,’ Libuda summarises the project. The research results are to be compiled in a type of modular system, allowing researchers to create bespoke, functional molecule/oxide interfaces. An ambitious endeavour: the scientists have to test the molecules on various surfaces and then examine them with regard to different properties. To ensure ideal test conditions, the researchers are using simplified models. ‘We have to be able to control the experimental set-up right down to the smallest atom. This is why we only use surfaces where we know the exact location of every atom,’ Libuda explains the researchers’ approach. The scientists from the Faculty of Sciences and the Faculty of Engineering are not only researching different molecules and carrier surfaces, they are also examining various aspects of their properties. ‘If you look through a microscope, you see the molecule as a little bump. The location of the molecule on the surface may be clearly visible, but the microscope does not tell you anything about chemical bonds. Another group is then tasked with that part,’ Libuda explains. Further information: Prof. Dr. Jörg Libuda Phone: +49 (0)9131 85 27308
Zuckerrübe (Bild: 4028mdk09, Wikimedia Commons)

Sugar beet (Picture: 4028mdk09, Wikimedia Commons)

How does the sugar get into the beet? This question has been investigated by researchers at FAU’s Division of Molecular Plant Physiology in collaboration with colleagues from the universities of Kaiserslautern, Cologne and Würzburg, and the companies Südzucker AG and KWS Saat AG. They have discovered a previously unknown mechanism which could be used to increase the sugar content of sugar beet in the future. The researchers’ findings have recently been published in the journal Nature Plants. (DOI: 10.1038/nplants.2014.1)

Alongside sugarcane, sugar beet – the scientific name of which is Beta vulgaris – is the most important crop that sugar can be extracted from. Its white root can also be used to produce ethanol, a type of biofuel. Sugar beet is therefore a rich source of energy and around one fifth of a high-quality, fresh sugar beet cultivated using conventional methods can consist of sugar. This makes sugar beet an important economic factor for rural areas.

Stimulated by energy from sunlight, sugar beet’s green leaves convert carbon dioxide in the air and water from the soil into sucrose. The plant stores this sugar as an energy reserve in its root. However, until recently, researchers were not able to explain what happens on a molecular level when a sugar beet fills its enormous sugar store. The FAU researchers and their colleagues spent three years investigating this phenomenon. Their work was funded by the Federal Ministry of Education and Research.

Protein controls sugar transport

The researchers discovered a previously unknown protein that transports the sugar to the vacuoles in the sugar beet’s cells. Vacuoles are an important organelle found in all plant cells. In sugar beet’s cells they function as powerful stores which absorb the sugar during the first year of growth. When sugar beet is processed the sugar is released from these cells and then crystallised when the water is made to evaporate. The researchers were able to identify and characterise the molecular structure of the protein that transports the sugar to the stores.

Their goal now is to cultivate sugar beet which produces more of this protein, enabling it to store larger quantities of sugar. ‘This would allow farmers to use agricultural land much more effectively and provide more sugar and raw material for biofuels,’ says FAU biologist Dr. Petra Wirsching.

Further information:

Dr. Petra Wirsching
Phone: +49 9131 8528200

Prof. Dr. Norbert Sauer
Phone:+49 9131 8528211