Researchers have found a method to overcome the chemical intractability of cellulose, thus allowing it to be converted efficiently into bioethanol. That means there is greater potential of waste plant matter to replace oil as a fuel source.
They identified the molecular mechanism behind an enzyme found in fungi which can degrade the cellulose chains of plant cell walls to release shorter sugars for biofuels.
This represents a major breakthrough as cellulose is the world's most abundant biopolymer. Global generation of cellulose is equivalent in energy to 670 billion barrels of oil – some 20 times the current annual global oil consumption. The discovery opens the way for the industrial production of fuels and chemicals from plentiful and renewable cellulose in waste plant matter.
This removes the major constraint on the production of bioethanol from cellulose the stability of which had previously thwarted previous efforts to make effective use of it for biofuels. The researchers found a way of initiating effective oxidative degeneration of cellulose using the copper-dependent TaGH61 enzyme to overcome the chemical inertness of the material.
Professor Gideon Davies from the University of York said, "Cracking cellulose represents one of the principal industrial and biotechnological challenges of the 21st century. Industrial production of fuels and chemicals from this plentiful and renewable resource holds the potential to displace petroleum-based sources, thus reducing the associated economic and environmental costs of oil and gas production. Events at Fukushima and the continuing instability in major oil producing countries only highlight the need for a balanced energy portfolio."
Claus Crone Fuglsang, Managing Director at Novozymes' research labs in Davis, California said, "Scientists have worked to figure out how to break down plant matter for the past 50-60 years. The impressive effect of GH61 was established a few years back and today it is a key feature of our Cellic CTec products.
"Fully understanding the mechanism behind GH61 is important in the context of commercial production of biofuel from plant waste and a true scientific paradigm shift. This discovery will continue to drive advances in production of other biobased chemicals and materials in the future."
The research was published in the Proceedings of the National Academy of Sciences (PNAS)