Enzyme May Help Unlock Biofuels From Waste
Author: Alister Doyle
Biomass, the unused portions of logged trees such a branches and the tree tops, sit at the Old Town Fuel and Fiber mill to be burned to generate electricity in Old Town, Maine, June 2, 2009.
Photo: Brian Snyder
A new chemical process may help unlock biofuels from trees and plant waste in a shift from using food crops such as sugar cane to generate fuel, scientists said Thursday.
They said they found an enzyme that helped break down chitin, a stiff material similar to woody cellulose that is found in the skeletons of crustaceans -- such as lobsters or crabs -- as well as insects.
"We regard this as a breakthrough," Gustav Vaaje-Kolstad, a Norwegian scientist who led the study in the journal Science, told Reuters. "Our goal is to make more valuable production from waste."
Other scientists are also developing ways to accelerate the breakdown of "biomass" waste ranging from sawdust to citrus peel that could create a new generation of biofuels. Biofuels help cut use of fossil fuels blamed for stoking global warming.
In his lab in Aas near Oslo, Vaaje-Kolstad showed off a vial of cloudy white liquid where the enzyme had broken down a sample of chitin. Alongside was another vial without the catalyst with flakes of chitin lying at the bottom in clear liquid.
"There are strong indications that similar enzymes exist that work on cellulose," Vaaje-Kolstad and colleagues at the Norwegian University of Life Sciences wrote.
The enzymes seem to make wood, for instance, swell up and break down, he said. "One of the most important bottlenecks in producing second generation biofuels is the process of going from biomass to soluble sugars," he said.
Biofuels are far easier to make from crops such as sugar cane, sunflowers or maize, for instance. But that means using cropland to generate fuel, making fuel compete with food supplies for a rising human population.
The scientists used an enzyme from the bacterium Serratia marcescens, which seems to cause a reaction on the surface of crystallized chitin. That primes the chitin for breakdown by other enzymes.
Vaaje-Kolstad said the new method broke down samples of chitin within about 2 hours, far faster than a previous method they found 5 years ago that takes about 48 hours.
He said that further work was needed to see if it would work on a bigger scale. "We are working on a laboratory scale. Sometimes these things are not applicable on a large scale. But we think that it should be possible," he said.
(Editing by Janet Lawrence)