In a breakthrough, scientists have developed a new technique to produce cheap and environmentally friendly second-generation biofuel from dead plant tissue.
The process as used today needs expensive enzymes, and large companies dominate this market, researchers said.
Now Danish and Iraqi researchers have developed a new technique that avoids the expensive enzymes.
Researchers said the production of second generation biofuels thus becomes cheaper, probably attracting many more producers and competition, and this may finally bring the price down.
Bioethanol, which is made from the remains of plants after other parts have been used as food or other agricultural products, and therefore termed "second generation," is seen as a strong potential substitute candidate.
Corn cubs and sugar canes are in fact plant parts that can also be used directly as food, so there is a great public resistance to accept producing this kind of bioethanol.
A big challenge is therefore to become able to produce bioethanol from plant parts, which cannot be used for food.
The goal is to produce bioethanol from cellulose. Cellulose is very difficult to break down, and therefore cannot directly be used as a food source, researchers said.
"But the patented enzymes are expensive to buy. We are proud to now introduce a completely enzyme-free technique that is not patented and not expensive. The technique can be used by everybody," said Per Morgen from University of Southern Denmark.
Together with colleagues from the University of Baghdad and Al-Muthanna University in Iraq, he said that it is not an enzyme, but an acid that plays the main role in the new technique.
The acid is called RHSO3H, and it is made on the basis of rice husks. The ashes from burnt rice husks have a high content of silicate, and this is the important compound in the production of the new acid.
The scientists paired silicate particles with chlorosulfonic acid and this made the acid molecules attach themselves to the silicate compounds.
"The result was an entirely new molecule - the acid RHSO3H - which can replace the enzymes in the work of breaking down cellulose to sugar," said Morgen.