The bright yellow fields of oilseed rape are a familiar sight at this time of year, but for scientists what lies beneath is just as exciting.
Researchers at the Institute of Food Research are looking at how to turn straw from oilseed rape into biofuel. Preliminary findings are pointing at ways the process could be made more efficient, as well as how the straw itself could be improved.
Straw from crops such as wheat, barley, oats and oilseed rape is seen as a potential source of biomass for second generation biofuel production. Currently the UK produces around 12 million tonnes of straw. Although much is used for animal bedding, mushroom compost and energy generation, there still exists a vast surplus.
Straw contains a mix of sugars that could be used as a source of biofuels that do not compete with food production but instead represent a sustainable way of utilising waste. However, the sugars are in a form that makes them inaccessible to the enzymes that release them for conversion into biofuels, so pre-treatments are needed. The pre-treatments make the complex carbohydrates more accessible to enzymes that convert them to glucose, in a process called saccharification. This is then fermented by yeast into ethanol.
Using the facilities at the Biorefinery Centre on the Norwich Research Park, Professor Keith Waldron and his team have been looking at the steps needed to unlock the sugars tied up in the tough straw structure. In particular, they have looked at the pre-treatment stage, focusing on steam explosion, which involves ‘pressure-cooking’ the biomass, to drive a number of chemical reactions. A rapid pressure-release then causes the material to be ripped open, to further improve accessibility.
They varied the temperature and duration of steam explosion and then used a variety of physical and biochemical techniques to characterise what effects varying the pre-treatments had on the different types of sugars before and after saccharification.
The amount of cellulose converted to glucose increased with the severity of the pretreatment. Saccharification efficiency is also associated with the loss of specific sugars, and subsequent formation of sugar breakdown products.
In a further study funded by the BBSRC / EPSRC Integrated Biorefining Research and Technology Club, the scientists discovered the key factors that determine the efficiency of saccharification. One particular compound, uronic acid, limited the rate at which enzymes worked. The final sugar yield was closely related to the removal of xylan, a common component of plant cell walls. The abundance of lignin, a ‘woody’ cell wall component, was positively related to the amount of available sugars.
These findings will help improve the efficiency by which straw can be converted to biofuels. For example, adding enzymes that more effectively remove xylan should improve yield. Controlling the level of lignin in the material should also help.
It may even be possible to improve the straw itself, for example to reduce the uronic acid content in the biomass, as suggested by these findings. In the main, oilseed rape has been bred to improve oilseed yield and disease resistance, without paying much attention to the straw. The IFR is working with colleagues at the University of York and the John Innes Centre to see whether there are ways of breeding more “biofuel-ready” varieties of oilseed rape, with the same yields of oilseed but with more amenable straw. In addition, a full understanding of the polysaccharides and other compounds made available during pretreatment may mean other valuable co-products, like platform chemicals, may be viably produced from the surplus straw.
Steam explosion of oilseed rape straw: Establishing key determinants of saccharification efficiency, Bioresource Technology 162, 175-183 doi: 10.1016/j.biortech.2014.03.115
Changes in the composition of the main polysaccharide groups of oil seed rape straw following steam explosion and saccharification, Biomass and Bioenergy 61 121-130 doi: 10.1016/j.biombioe.2013.12.003
Andrew Chapple | Eurek Alert!
Unidentified spectra detector
28.06.2016 | European Molecular Biology Laboratory - European Bioinformatics Institute
Freiburg Biologists Explain Function of Pentagone
28.06.2016 | Albert-Ludwigs-Universität Freiburg im Breisgau
R2D2, a joint project to analyze and development high-TRL processes and technologies for manufacture of flexible organic light-emitting diodes (OLEDs) funded by the German Federal Ministry of Education and Research (BMBF) has been successfully completed.
In contrast to point light sources like LEDs made of inorganic semiconductor crystals, organic light-emitting diodes (OLEDs) are light-emitting surfaces. Their...
High resolution rotational spectroscopy reveals an unprecedented number of conformations of an odorant molecule – a new world record!
In a recent publication in the journal Physical Chemistry Chemical Physics, researchers from the Max Planck Institute for the Structure and Dynamics of Matter...
Strands of cow cartilage substitute for ink in a 3D bioprinting process that may one day create cartilage patches for worn out joints, according to a team of engineers. "Our goal is to create tissue that can be used to replace large amounts of worn out tissue or design patches," said Ibrahim T. Ozbolat, associate professor of engineering science and mechanics. "Those who have osteoarthritis in their joints suffer a lot. We need a new alternative treatment for this."
Cartilage is a good tissue to target for scale-up bioprinting because it is made up of only one cell type and has no blood vessels within the tissue. It is...
Physicists in Innsbruck have realized the first quantum simulation of lattice gauge theories, building a bridge between high-energy theory and atomic physics. In the journal Nature, Rainer Blatt‘s and Peter Zoller’s research teams describe how they simulated the creation of elementary particle pairs out of the vacuum by using a quantum computer.
Elementary particles are the fundamental buildings blocks of matter, and their properties are described by the Standard Model of particle physics. The...
A year and a half on the outer wall of the International Space Station ISS in altitude of 400 kilometers is a real challenge. Whether a primordial bacterium...
28.06.2016 | Event News
09.06.2016 | Event News
24.05.2016 | Event News
28.06.2016 | Physics and Astronomy
28.06.2016 | Life Sciences
28.06.2016 | Physics and Astronomy