Double for nothing: waste from sugar processing could soon find its way into Brazilian gas tanks--as fuel.

A Brazilian company has devised a way to double the amount of ethanol extracted--used in Brazil as automotive fuel--from sugar cane. With gasoline shooting toward US$50 a barrel and possibly spiking to $80 or higher soon, that's great news for developing economies. Currently, one in five Brazilian cars on the road bums ethanol, mixed at the pump as a 75% gasoline, 25% ethanol mixture.

Typically, sugar cane processors make equal proportions of sugar and ethanol. Half of the cane juice is crystallized into sugar and the other half, which can't crystallize, is a syrupy molasses that is fermented with yeast to make ethanol. Crushed sugar cane refuse, known as bagasse, is burned in a small power plant to provide electricity for the production process.

Researchers at Dedini Industrias de Base, which normally builds sugar-ethanol plants and makes replacement parts for industry--for nearly two decades believed they could make much better use of bagasse by recycling it into ethanol rather than on-the-spot electricity.

Dedini, which reported $250 million in sales in 2004, began tinkering with this conversion process, which it calls Dedini Bapid Hydrolysis (DHFR), in the late 1980s. The company is now completing the engineering plans for an industrial-scale plant that will produce 50,000 liters a day of ethanol--the first of its kind anywhere--which it expects to be producing within two years. It has invested $9 million so far in getting the plant from drawing board to reality.

"If what Dedini says is true and I can double my ethanol production using the same amount of sugar cane, how can I not such a revolutionary technology?" asked Joamir Alves, the president of sugar-ethanol mill Usinas Silo Luiz in Sao Paulo state. "And while I'll use bagasse to make ethanol, rather than to generate electricity, I can use sugar-cane straw to thermo-generate enough electricity for the entire mill."

Jose Oliverio, Dedini's vice president of operations, said that the process is cost effective because its reactor will be made of stainless steel, not costlier titanium and because 10 times less acid is needed, much less time is needed, and because the raw materials needed are already produced by sugar-cane processors at the reactor site. "Simply by processing the bagasse, you can double the amount of ethanol you produce," says Oliverio. "Or in other words, the same sugar cane acreage can produce double the amount of ethanol."

Researchers in other countries have tried to perfect this bagasse-to-ethanol process but they have always hit a wall. Traditionally, the method involved mixing bagasse with water and sulfuric acid and heating the solution to form five- and six-carbon sugars, which would then be fermented with yeast to make ethanol. But lignin--a complex polymer in the cell walls of cane and bagasse that gives it structural rigidity--is a tough, outer shield that prevents the acid from breaking down bagasse into sugars. To work, acid concentrations and temperatures must be pushed so high that they instead destroy the sugars before they can be fermented.

In the Dedini process, a solvent is added to mix, dissolving the lignin and thus allowing the acid to attack the bagasse, breaking it down into sugars. Because it requires less acid and far less time--15 minutes rather than four to six hours--the sugar does not oxidize. Dedini's breakthrough was adding the solvent to the mix and designing a continuous-process reactor to extract the resulting sugar-water liquor. Dedini tested 26 solvents before settling on ethanol, which had the best cost-benefit ratio. The company has patented the process in many countries around the world and is now perfecting temperature levels and acid concentrations.

Turnkey. Oliverio believes that the main buyers of Dedini's bagasse-to-ethanol technology and plants--estimated to cost $12 million to $15 million--will be sugar ethanol producers in Latin America, India, Australia and South Africa. "Dedini has already been contacted by 40 companies in Brazil and abroad, some of whom want to license the technology and some of whom want to buy the turnkey plant," says Oliverio.

U.S. and European countries have developed technologies to break down corn and wheat refuse using enzymes, instead of lignin solvents, but the enzyme costs are too high to make the process commercially viable, according to Regis Leal, a chemical engineer and researcher in energy planning at the Universidad Estadual de Campinas. "Dedini appears to be the only entity that has developed a commercially-viable, industrial-scale means of turning refuse from processed crops into ethanol," Leal says.

MICHAEL KEPP, RIO DE JANEIRO