A worker harvests sugar cane at a plantation in Santa Rita do Passa Quatro, about 200km south-east of Sao Paulo, in this September 8, 2005 file photo. The governments of Cuba and Venezuela contend that the world's push for ethanol-driven energy will hurt world food supplies. - Reuters

SAO PAULO, Brazil (Reuters):

A Brazilian company said yesterday that it has come up with a way to produce ethanol on an industrial scale from plant waste. The development could revolutionise the industry by boosting fuel output without depleting supplies of food staples such as corn or sugar.

Brazil's Dedini, the leading manufacturer of sugar and biofuel equipment, said it has developed an economically viable ethanol production technology based on cellulose.

"It is cost-competitive with oil at US$42 a barrel," said Dedini operations vice-president, Jos Luiz Oliverio at a seminar at Sao Paulo's Industry Federation, Fiesp.

Weaken critics' arguments

As cellulose ethanol technology advances and becomes more widely used, it could weaken arguments by critics, such as Cuba's Fidel Castro or Venezuela's Hugo Chavez, that the world's push to produce more ethanol will tax world food supplies and create more global hunger.

Dedini has commercial ties with all of Brazil's 357 sugar and ethanol mills and is the main supplier of co-generation plants, sugar refineries and ethanol distilleries.

Dedini's Sao Luiz Mill in Sao Paulo state began producing cellulose bioethanol from bagasse - the leftover cane stalk after the sucrose is pressed out - at about 40 cents a litre in 2002. But production costs have fallen with improvements in technology to below 27 cents a litre, Oliverio said.

Brazil has the world's most advanced biofuels market, with 30 years of experience in national ethanol production. The state-of-the-art ethanol mills can produce the biofuel from cane sucrose at or below 18 cents a litre, experts say.

The bagasse is most often burned in co-generation electric power plants on-site to run operations at the mill, or excess is sold to nearby industries such as orange juice processors for burning or to cattle or pig ranchers for feed.

Many of Brazil's cane mills had even installed out-of-date inefficient blast furnaces so they would not be left with excess bagasse, for which they would have to pay for disposal.

"This will be able to boost a mill's ethanol output by 30 per cent without planting one more cane stalk," Oliverio said.

He said the technology is based on a chemical acid wash that breaks up the protective lignin fibres in the cane stalk and allows a type of sugar cell to be washed out.

"This type of acid method typically inhibits fermentation of the syrup that comes from the sugars in the bagasse, so mills will have to figure out how to overcome this," said Professor Carlos Rossel at the UNICAMP university.

But Oliverio said it wasn't a problem as their system uses a very diluted acid to free the sugars in the cane.

ENZYMES

Many researchers in the area of cellulose technology believe enzymes, or natural proteins that accelerate the breakdown of the lignin fibers, will be used in future cellulose ethanol production.

But Rossel and Professor Elba Bom at Rio de Janiero's UFRJ University pointed to two challenges: reducing the exorbitantly high cost of industrial production of enzymes, and shortening the time required for the enzymes to act on the lignin.

Bom said her research team has been developing methods of leaving shredded bagasse outside in something like a large compost heap to allow naturally occurring enzymes to go to work in a pre-treatment stage to loosen the lignin's hold on the sugar, but this requires as much as a weak.