Project

Genetic improvement of miscanthus for biomass production

Lignocellulose-rich crops, such as miscanthus, are receiving a lot of attention because their biomass can prevent greenhouse gas emissions. They are an alternative to fossil fuels such as oil. These crops could, therefore, play an important role in the European Union’s objective to obtain ten per cent of energy from sustainable sources by 2020.

Miscanthus, a giant perennial grass, is an excellent resource for biomass production, the basis for green energy. However, the cultivation and the crop have two major bottlenecks: propagation of the variety presents problems and it is difficult to release the sugars in biomass. Plant Research International, part of Wageningen UR,  is researching solutions to this. It is carrying out research projects to genetically improve the miscanthus.

High-grade biomass

This research is in cooperation with IBERS, a research institute in Wales in the United Kingdom.
The researchers want to gain an increased understanding of the genetics of properties that are of importance for the improvement of miscanthus. Ultimately, this has to result in a crop that propagates well from seed and that gives a high yield of quality high-grade biomass.
To be able to produce biomass, sugars in the crop are converted into ethanol, the basis of biofuel. A good bioconversion of cell wall sugars is necessary for a high combustion quality for the generation of heat and electricity.
Additionally, there is research into the tolerance for abiotic stress in this crop. Abiotic stress occurs when a crop has to grow under difficult circumstances, such as extreme drought.

Biofuels

Miscanthus supplies a crop with an abundance of stalks that is excellent for use in the generation of heat and electricity. The biomass is now chiefly used as a raw material for the production of biofuels such as bio-ethanol.
The crop which was originally tropical in nature has many advantages:
• it thrives well in a moderate European climate;
• it is a C4 grass, which means that it has the ability to convert carbon dioxide into sugars very efficiently;
• miscanthus requires minimal fertilisers and tillage;
• it is a perennial crop that can be cultivated for at least 15 to 25 years;
• the cultivation of miscanthus offers a new source of income to the agricultural sector.

Bottlenecks

One bottleneck of this crop is that it is difficult to release the sugars. Those sugars are required for the conversation to ethanol, in turn required to produce biofuel. Through the process of photosynthesis, carbon dioxide is converted into sugars in the crop through sunlight. In miscanthus, the light is mainly captured in lignocellulose: cellulose and hemicellulose and lignin. The sugars in the aforementioned cell wall components are difficult for enzymes or micro-organisms, required for the production of ethanol, to access. Lignin plays an important role in this and impedes the conversion of the sugars into ethanol.

The cultivation of this crop is a second bottleneck. There is one type of miscanthus that is very suitable for the production of biomass. This type is sterile and it is therefore not possible to propagate this from seed. Growers therefore still have to depend on the purchase of rhizomes (rootstocks) or an expensive in vitro procedure in a laboratory in order to obtain new plants.