Due to dwindling fossil fuel supplies and increasing interest in reducing carbon dioxide emissions, significant work is being undertaken to improve biofuels as an alternative fuel product.
The most significant advantage of biofuels is that they are renewable, unlike fossil resources which are finite. Although biofuels have been used since the early 1900s, the supply, price and efficiency of using non-renewable sources of energy such as coal, petroleum and natural gas has led to the latter’s dominance in the energy sector.
Professor Chris Grof and his team from the Plant Science Group at the University of Newcastle, have developed a superior cellulase enzyme to assist in the production of biofuel that is both cost effective and more efficient than other available enzymes.
“At present cellulase enzymes tend to be produced in large volumes by engineered bacteria. Once the enzyme has been isolated, it is added to plant biomass, where it catalyses a chemical reaction that assists in preparing the plant biomass for the subsequent steps in production of biofuel,” said Professor Grof.
“The advantage of our enzyme is it has an ‘in planta’ capability. This means that plants may be generated that are capable of producing the cellulase enzyme. Production of the enzyme in the plant can be ‘switched on’ shortly before harvest, so the reaction can be initiated before the plant is even harvested.”
The new enzyme can also be produced by yeast or bacteria and harvested as previously described; however, the new method may be more efficient as the expensive enzyme is produced within the plants themselves.
Dr Caitlin Byrt, who is also working on the project, says “cellulose is an abundant polymer, but very active cellulase enzymes are needed to break the cellulose up into sugar molecules so it can be turned into a combustible fuel, by the process of fermentation.”
She explains “In our particular project we are using Sorghum. The celluase enzyme breaks down the cellulose in the Sorghum plant cell walls. This makes it easier for the cellulose in the cell wall to be converted to glucose, which is used to make ethanol.”
Although the enzyme is intended for use in the production of bioethanol, there is the potential for it to be used in a variety of other industries. These include applications in textiles, detergents, paper or pulp materials, plastics and production of hydrocarbons.
The Plant Science Group has already conducted preliminary analysis of the enzyme, with very positive results, and hopes to test the production process in a pilot plant facility in the future. They are also seeking industry partners to license or assist in the commercial development of this technology.