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!
More than just a mechanical barrier – epithelial cells actively combat the flu virus
04.05.2016 | Helmholtz-Zentrum für Infektionsforschung
Discovery of a fundamental limit to the evolution of the genetic code
03.05.2016 | Institute for Research in Biomedicine (IRB Barcelona)
Using an ultra fast-scanning atomic force microscope, a team of researchers from the University of Basel has filmed “living” nuclear pore complexes at work for the first time. Nuclear pores are molecular machines that control the traffic entering or exiting the cell nucleus. In their article published in Nature Nanotechnology, the researchers explain how the passage of unwanted molecules is prevented by rapidly moving molecular “tentacles” inside the pore.
Using high-speed AFM, Roderick Lim, Argovia Professor at the Biozentrum and the Swiss Nanoscience Institute of the University of Basel, has not only directly...
If a person pushes a broken-down car alone, there is a certain effect. If another person helps, the result is the sum of their efforts. If two micro-particles are pushing another microparticle, however, the resulting effect may not necessarily be the sum their efforts. A recent study published in Nature Communications, measured this odd effect that scientists call “many body.”
In the microscopic world, where the modern miniaturized machines at the new frontiers of technology operate, as long as we are in the presence of two...
Researchers from the Max Planck Institute Stuttgart have developed self-propelled tiny ‘microbots’ that can remove lead or organic pollution from contaminated water.
Working with colleagues in Barcelona and Singapore, Samuel Sánchez’s group used graphene oxide to make their microscale motors, which are able to adsorb lead...
Neutron scattering and computational modeling have revealed unique and unexpected behavior of water molecules under extreme confinement that is unmatched by any known gas, liquid or solid states.
In a paper published in Physical Review Letters, researchers at the Department of Energy's Oak Ridge National Laboratory describe a new tunneling state of...
Honeycomb structures as the basic building block for industrial applications presented using holo pyramid
Researchers of the Alfred Wegener Institute (AWI) will introduce their latest developments in the field of bionic lightweight design at Hannover Messe from 25...
27.04.2016 | Event News
15.04.2016 | Event News
12.04.2016 | Event News
04.05.2016 | Physics and Astronomy
04.05.2016 | Physics and Astronomy
04.05.2016 | Materials Sciences